Lighting device

ABSTRACT

A lighting device is specified. The lighting device comprises a phosphor having the general molecular formula (MA)a(MB)b(MC)c(MD)d(TA)e(TB)f(TC)g(TD)h(TE)i(TF)j(XA)k(XB)l(XC)m(XD)n:E. In this case, MA is selected from a group of monovalent metals, MB is selected from a group of divalent metals, MC is selected from a group of trivalent metals, MD is selected from a group of tetravalent metals, TA is selected from a group of monovalent metals, TB is selected from a group of divalent metals, TC is selected from a group of trivalent metals, TD is selected from a group of tetravalent metals, TE is selected from a group of pentavalent elements, TF is selected from a group of hexavalent elements, XA is selected from a group of elements which comprises halogens, XB is selected from a group of elements which comprises O, S and combinations thereof, XC=N and XD=C and E=Eu, Ce, Yb and/or Mn. The following furthermore hold true: a+b+c+d=t; e+f+g+h+i+j=u; k+l+m+n=v; a+2b+3c+4d+e+2f+3g+4h+5i+6j−k−2l−3m−4n=w; 0.8≤t≤1; −3.5≤u≤4; 3.5≤v≤4; (−0.2)≤w≤0.2 and 0≤m&lt;0.875 v and/or v≥1&gt;0.125 v.

RELATED APPLICATIONS

The present application is a divisional of U.S. patent application Ser.No. 16/302,724, filed on Nov. 19, 2018 which is a National StageApplication of PCT application No. PCT/EP2017/070343 filed on Aug. 10,2017, which claims priority from German application No. 10 2016 114996.9 filed on Aug. 12, 2016 and from German application No. 10 2016 121694.1 filed on Nov. 11, 2016, all of which are incorporated herein byreference in their entirety.

TECHNICAL FIELD

Various embodiments relate to a lighting device, in particular aconversion light-emitting diode (conversion LED).

BACKGROUND

Phosphors which can be efficiently excited by ultraviolet, blue or greenprimary radiation and have an efficient emission in the blue, green,yellow, red or deep-red spectral range are of very great interest forthe production of white and colored conversion LEDs. Conversion LEDs areused for many applications, for example for general lighting, displaybacklighting, signage, display panels, in automobiles and in numerousfurther consumer products. Conversion LEDs for the backlighting ofdisplay elements, such as displays, for example, differ greatly fromconversion LEDs for general lighting. The requirements made ofconversion LEDs for general lighting consist, in particular, in a highluminous efficiency combined with a high efficiency, a high colorrendering index and a color temperature of less than 3500 K. ConversionLEDs for the backlighting of display elements require, in particular,phosphors having narrowband emission in the blue, green and red spectralrange in order to cover the widest possible color space. Moreover, thereis great demand for colored conversion LEDs which render colors adaptedto consumer desires (so-called “color on demand” applications).

Previous white-emitting conversion LEDs for general lighting andbacklighting use a semiconductor chip which emits a blue primaryradiation, and a red and green phosphor. What is disadvantageous aboutthis solution is that the epitaxially grown semiconductor chips, basedfor example on GaN or InGaN, can have fluctuations in the peakwavelength of the emitted primary radiation. This leads to fluctuationsin the white overall radiation, such as a change in the color locus andthe color rendering, since the primary radiation contributes the blueportion to the overall radiation. This is problematic particularly whena plurality of semiconductor chips are used in a device.

In order to avoid fluctuations, the semiconductor chips are sorted inaccordance with their color loci (“binning”). The narrower thetolerances set with regard to the wavelength of the emitted primaryradiation, the higher the quality of conversion LEDs which consist ofmore than one semiconductor chip. However, even after sorting withnarrow tolerances, the peak wavelength of the semiconductor chips canchange significantly in the case of variable operating temperatures andforward currents. In general lighting and other applications, this canlead to a change in the optical properties, such as the color locus andthe color temperature.

In the backlighting of display elements, such as displays intelevisions, computer monitors, tablets and smartphones, manufacturersendeavor to render the colors in a vivid and lifelike way, since this isvery attractive to consumers. The backlighting of display elementstherefore requires light sources having very narrowband emissions, thatis to say a small full width at half maximum, in the green, blue and redspectral range in order to cover the widest possible color space. Aslight sources for backlighting applications, predominantly ablue-emitting semiconductor chip is combined with a phosphor having apeak wavelength in the green spectral range and a phosphor having a peakwavelength in the red spectral range.

Conversion LEDs for backlighting applications conventionally use asgreen phosphor, for example, an yttrium aluminum garnet, a lutetiumaluminum garnet or a β-SiAlON (Si_(6−z)Al_(z)O_(z)N_(8−z):RE orSi_(6−x)Al_(z)O_(y)N_(8−y):RE_(z) where RE=rare earth metal). However,yttrium aluminum garnet has an emission peak having a large full widthat half maximum, such that, as a result of considerable filter losses,the achievable color space is restricted and the efficiency is alsoreduced. β-SiAlON with a full width at half maximum of less than 60 nmhas a narrowband emission in the green spectral range which leads to amore saturated green rendering than with a garnet phosphor. However,β-SiAlONs lack a good internal and external quantum efficiency, whichmakes the entire backlighting not very efficient. Furthermore, theproduction of these phosphors requires very high temperatures andexpensive equipment. The production of the phosphor is thus veryexpensive and thus so is the production of conversion LEDs comprisingsaid phosphor.

Quantum dots, on account of their very narrowband emission, are alsoused for converting primary radiation for backlighting applications.However, quantum dots are very unstable. Moreover, most commerciallyavailable quantum dots comprise harmful elements such as Hg or Cd, theconcentration of which is limited in commercial electrical andelectronic devices under the RoHS regulations (“reduction of hazardoussubstances”, EU Directive 2011/65/EU).

Known blue-green to green phosphors for conversion LEDs are for examplethe phosphors Ca₈Mg(SiO₄)₄Cl₂:Eu, (Sr,Ba)₂SiO₄:Eu and Lu₃(Al,Ga)₅O₁₂:Ce.However, conversion LEDs comprising these phosphors have inadequatecolor purity and cannot achieve specific color loci, for which reasonthey are not appropriate for many “color on demand” applications.

SUMMARY

The object of the present disclosure is to specify a lighting device, inparticular a conversion LED, which is improved by comparison with theprior art and which can be used in particular for general lighting,backlighting and “color on demand” applications.

The object is achieved by means of a lighting device as claimed inindependent claim 1. Advantageous embodiments and developments of thepresent disclosure are respectively specified in the dependent claims.

A phosphor is specified. The phosphor has the general molecular formula:(MA)_(a)(MB)_(b)(MC)_(c)(MD)_(d)(TA)_(e)(TB)_(f)(TC)_(g)(TD)_(h)(TE)_(i)(TF)_(j)(XA)_(k)(XB)_(l)(XC)_(m)(XD)_(n).

In this case, MA is selected from a group of monovalent metals, MB isselected from a group of divalent metals, MC is selected from a group oftrivalent metals, MD is selected from a group of tetravalent metals, TAis selected from a group of monovalent metals, TB is selected from agroup of divalent metals, TC is selected from a group of trivalentmetals, TD is selected from a group of tetravalent metals, TE isselected from a group of pentavalent elements, TF is selected from agroup of hexavalent elements, XA is selected from a group of elementswhich comprises halogens, XB is selected from a group of elements whichcomprises O, S and combinations thereof, XC=N and XD=C. The followingfurthermore hold true:

-   -   a+b+c+d=t;    -   e+f+g+h+i+j=u    -   k+l+m+n=v    -   a+2b+3c+4d+e+2f+3g+4h+5i+6j−k−2l−3m−4n=w    -   0.8≤t≤1    -   3.5≤u≤4    -   3.5≤v≤4    -   (−0.2)≤w≤0.2.

In accordance with at least one embodiment, the phosphor compriseswithin its molecular formula at least Eu, Ce, Yb and/or Mn. Eu, Ce, Yband/or Mn serve as activators of the phosphor which is responsible forthe emission of radiation. The phosphor can thus have in particular thefollowing formula:(MA)_(a)(MB)_(b)(MC)_(c)(MD)_(d)(TA)_(e)(TB)_(f)(TC)_(g)(TD)_(h)(TE)_(i)(TF)_(j)(XA)_(k)(XB)_(l)(XC)_(m)(XD)_(n):E,wherein E=Eu,Ce,Yb and/or Mn.

Here and hereinafter phosphors are described on the basis of molecularformulae. In the case of the specified molecular formulae it is possiblefor the phosphor to comprise further elements for instance in the formof impurities, wherein these impurities taken together shouldadvantageously have at most a proportion by weight in the phosphor of atmost 1 per mille or 100 ppm (parts per million) or 10 ppm.

In accordance with at least one embodiment, the following holds true forthe phosphor having the general molecular formula(MA)_(a)(MB)_(b)(MC)_(c)(MD)_(d)(TA)_(e)(TB)_(f)(TC)_(g)(TD)_(h)(TE)_(i)(TF)_(j)(A)_(k)(XB)_(l)(C)_(m)(XD)_(n)or(MA)_(a)(MB)_(b)(MC)_(c)(MD)_(d)(TA)_(e)(TB)_(f)(TC)_(g)(TD)_(h)(TE)_(i)(TF)_(j)(XA)_(k)(XB)_(l)(XC)_(m)(XD)_(n):E:0≤m<0.875vand/or v≥1>0.125v.

A lighting device comprising a phosphor is specified. The phosphor hasthe following general molecular formula:(MA)_(a)(MB)_(b)(MC)_(c)(MD)_(d)(TA)_(e)(TB)_(f)(TC)_(g)(TD)_(h)(TE)_(i)(TF)_(j)(XA)_(k)(XB)_(l)(XC)_(m)(XD)_(n),wherein

-   -   MA is selected from a group of monovalent metals which comprises        Li, Na, K, Rb, Cs, Cu, Ag and combinations thereof,    -   MB is selected from a group of divalent metals which comprises        Mg, Ca, Sr, Ba, Zn, Mn, Eu, Yb, Ni, Fe, Co and combinations        thereof,    -   MC is selected from a group of trivalent metals which comprises        Y, Fe, Cr, Sc, In, rare earth metals and combinations thereof,    -   MD is selected from a group of tetravalent metals which        comprises Zr, Hf, Mn, Ce and combinations thereof,    -   TA is selected from the group of monovalent metals which        comprises Li, Na, Cu, Ag and combinations thereof,    -   TB is selected from a group of divalent metals which comprises        Mg, Zn, Mn, Eu, Yb, Ni and combinations thereof,    -   TC is selected from a group of trivalent metals which comprises        B, Al, Ga, In, Y, Fe, Cr, Sc, rare earth metals and combinations        thereof,    -   TD is selected from a group of tetravalent metals which        comprises Si, Ge, Sn, Mn, Ti, Zr, Hf, Ce and combinations        thereof,    -   TE is selected from a group of pentavalent elements which        comprises P, Ta, Nb, V and combinations thereof,    -   TF is selected from a group of hexavalent elements which        comprises W, Mo and combinations thereof,    -   XA is selected from a group of elements which comprises F, Cl,        Br and combinations thereof,    -   XB is selected from a group of elements which comprises O, S and        combinations thereof,    -   XC=N    -   XD=C    -   a+b+c+d=t    -   e+f+g+h+i+j=u    -   k+l+m+n=v    -   a+2b+3c+4d+e+2f+3g+4h+5i+6j−k−2l−3m−4n=w    -   0.8≤t≤1    -   3.5≤u≤4    -   3.5≤v≤4    -   (−0.2)≤w≤0.2 and        0≤m<0.875 v and/or v≥1>0.125 v. The phosphor contains in        particular within its molecular formula at least Eu, Ce, Yb        and/or Mn and has in particular the molecular formula        (MA)_(a)(MB)_(b)(MC)_(c)(MD)_(d)(TA)_(e)(TB)_(f)(TC)_(g)(TD)_(h)(TE)_(i)(TF)_(j)(XA)_(k)(XB)_(l)(XC)_(m)(XD)_(n):E        where E=Eu,Ce,Yb and/or Mn.

The assignment of the elements to MA, MB, MC, MD, TA, TB, TC, TD, TE, TFis based in particular on the arrangement thereof within the crystalstructures of the phosphors. In particular, in this case, within thecrystal structures TA, TB, TC, TD, TE and/or TF are surrounded by XA,XB, XC and/or XD and the resultant structural units are linked viacommon corners and edges. The corner and edge linkage of the structuralunits results in particular in the formation of cavities or channels inwhich MA, MB, MC and/or MD are arranged. On account of this assignment,it is possible for the possible elements in MA, MB, MC, MD, TA, TB, TC,TD, TE and TF to overlap.

In accordance with at least one embodiment, the phosphor has thefollowing general molecular formula:(MA)_(a)(MB)_(b)(TA)_(e)(TB)_(f)(TC)_(g)(TD)_(h)(XC)_(m)(XB)_(l),wherein

-   -   MA is selected from a group of monovalent metals which comprises        Li, Na, K, Rb, Cs, Cu, Ag and combinations thereof,    -   MB is selected from a group of divalent metals which comprises        Mg, Ca, Sr, Ba, Zn, Mn, Eu, Yb, Ni, Fe, Co and combinations        thereof,    -   TA is selected from a group of monovalent metals which comprises        Li, Na, Cu, Ag and combinations thereof,    -   TB is selected from a group of divalent metals which comprises        Mg, Zn, Mn, Eu, Yb, Ni and combinations thereof,    -   TC is selected from a group of trivalent metals which comprises        B, Al, Ga, In, Y, Fe, Cr, Sc, rare earths and combinations        thereof,    -   TD is selected from a group of tetravalent metals which        comprises Si, Ge, Sn, Mn, Ti, Zr, Hf, Ce and combinations        thereof,    -   XB is selected from a group of elements which comprises O, S and        combinations thereof,    -   XC=N    -   a+b=t    -   e+f+g+h=u    -   l+m=v    -   a+2b+e+2f+3g+4h−2l−3m=w    -   0.8≤t≤1    -   3.5≤u≤4    -   3.5≤v≤4    -   (−0.2)≤w≤0.2 and        0≤m<0.875 v and/or v≥l>0.125 v. The phosphor contains in        particular within its molecular formula at least Eu, Ce, Yb        and/or Mn and has in particular the molecular formula        (MA)_(a)(MB)_(b)(TA)_(e)(TB)_(f)(TC)_(g)(TD)_(h)(XC)_(m)(XB)_(l):E        where E=Eu, Ce, Yb and/or Mn. The following advantageously hold        true:    -   MA is selected from a group of monovalent metals which comprises        Li, Na, K, Rb, Cs and combinations thereof,    -   MB is selected from a group of divalent metals which comprises        Mg, Ca, Sr, Ba, Eu and combinations thereof,    -   TA is selected from a group of monovalent metals which comprises        Li, Na, Cu, Ag and combinations thereof,    -   TB is selected from a group of divalent metals which comprises        Eu,    -   TC is selected from a group of trivalent metals which comprises        B, Al, Ga, In and combinations thereof,    -   TD is selected from a group of tetravalent metals which        comprises Si, Ge, Sn, Mn, Ti and combinations thereof,    -   XB=O.

In one embodiment, the lighting device is a conversion light-emittingdiode.

A conversion light-emitting diode (conversion LED) is specified. Theconversion light-emitting diode (conversion LED) comprises a phosphor ofthe molecular formula (MA)_(a)(MB)_(b) (MC)_(c)(MD)_(d)(TA)_(e)(TB)_(f)(TC)_(g)(TD)_(h)(TE)_(i)(TF)_(j)(XA)_(k)(XB)_(l)(XC)_(m)(XD)_(n).

In this case, MA is selected from a group of monovalent metals, MB isselected from a group of divalent metals, MC is selected from a group oftrivalent metals, MD is selected from a group of tetravalent metals, TAis selected from a group of monovalent metals, TB is selected from agroup of divalent metals, TC is selected from a group of trivalentmetals, TD is selected from a group of tetravalent metals, TE isselected from a group of pentavalent elements, TF is selected from agroup of hexavalent elements, XA is selected from a group of elementswhich comprises halogens, XB is selected from a group of elements whichcomprises O, S and combinations thereof, XC=N and XD=C. The followingfurthermore hold true:

-   -   a+b+c+d=t;    -   e+f+g+h+i+j=u    -   k+l+m+n=v    -   a+2b+3c+4d+e+2f+3g+4h+5i+6j−k−2l−3m−4n=w    -   0.8≤t≤1    -   3.5≤u≤4    -   3.5≤v≤4    -   (−0.2)≤w≤0.2. The phosphor contains in particular within its        molecular formula at least Eu, Ce, Yb and/or Mn and has in        particular the molecular formula (MA)_(a)(MB)_(b)        (MC)_(c)(MD)_(d)(TA)_(e)        (TB)_(f)(TC)_(g)(TD)_(h)(TE)_(i)(TF)_(j)(XA)_(k)(XB)_(l)(XC)_(m)(XD)_(n):E        where E=Eu, Ce, Yb and/or Mn. In particular, the phosphor is        arranged in a conversion element.

In accordance with one embodiment, the lighting device, in particularthe conversion LED, comprises a primary radiation source configured toemit an electromagnetic primary radiation during operation of thelighting device, in particular of the conversion LED. Furthermore, thelighting device, in particular the conversion LED, comprises aconversion element arranged in the beam path of the electromagneticprimary radiation. The conversion element comprises a phosphorconfigured at least partly to convert the electromagnetic primaryradiation into an electromagnetic secondary radiation during operationof the lighting device, in particular of the conversion LED. Thephosphor has in particular the following molecular formula:(MA)_(a)(MB)_(b)(MC)_(c)(MD)_(d)(TA)_(e)(TB)_(f)(TC)_(g)(TD)_(h)(TE)_(i)(TF)_(j)(XA)_(k)(XB)_(l)(XC)_(m)(XD)_(n),wherein

-   -   MA is selected from a group of monovalent metals which comprises        Li, Na, K, Rb, Cs, Cu, Ag and combinations thereof,    -   MB is selected from a group of divalent metals which comprises        Mg, Ca, Sr, Ba, Zn, Mn, Eu, Yb, Ni, Fe, Co and combinations        thereof,    -   MC is selected from a group of trivalent metals which comprises        Y, Fe, Cr, Sc, In, rare earth metals and combinations thereof,    -   MD is selected from a group of tetravalent metals which        comprises Zr, Hf, Mn, Ce and combinations thereof,    -   TA is selected from a group of monovalent metals which comprises        Li, Na, Cu, Ag and combinations thereof,    -   TB is selected from a group of divalent metals which comprises        Mg, Zn, Mn, Eu, Yb, Ni and combinations thereof,    -   TC is selected from a group of trivalent metals which comprises        B, Al, Ga, In, Y, Fe, Cr, Sc, rear earth metals and combinations        thereof,    -   TD is selected from a group of tetravalent metals which        comprises Si, Ge, Sn, Mn, Ti, Zr, Hf, Ce and combinations        thereof,    -   TE is selected from a group of pentavalent elements which        comprises P, Ta, Nb, V and combinations thereof,    -   TF is selected from a group of hexavalent elements which        comprises W, Mo and combinations thereof,    -   XA is selected from a group of elements which comprises F, Cl,        Br and combinations thereof,    -   XB is selected from a group of elements which comprises O, S and        combinations thereof,    -   XC=N,    -   XD=C,    -   a+b+c+d=t    -   e+f+g+h+i+j=u    -   k+l+m+n=v    -   a+2b+3c+4d+e+2f+3g+4h+5i+6j−k−2l−3m−4n=w    -   0.8≤t≤1    -   3.5≤u≤4    -   3.5≤v≤4    -   (−0.2)≤w≤0.2 and        0≤m<0.875 v and/or v≥1>0.125 v. The phosphor contains in        particular within its molecular formula at least Eu, Ce, Yb        and/or Mn and has in particular the molecular formula        (MA)_(a)(MB)_(b)(MC)_(c)(MD)_(d)(TA)_(e)(TB)_(f)(TC)_(g)(TD)_(h)(TE)_(i)(TF)_(j)(XA)_(k)(XB)_(l)(XC)_(m)(XD)_(n):E        where E=Eu, Ce, Yb and/or Mn.        0≤m<0.875 v and/or v≥l>0.125 v means that the mol proportion of        XC, that is to say nitrogen, in the phosphor is below 87.5 mol %        relative to the total substance amount v of XA, XB, XC and XD        and/or the molar proportion of XB, that is to say oxygen and/or        sulphur, in the phosphor is above 12.5 mol % relative to the        total substance amount v of XA, XB, XC and XD.

The fact that the phosphor at least partly converts the electromagneticprimary radiation into an electromagnetic secondary radiation can mean,firstly, that the electromagnetic primary radiation is partly absorbedby the phosphor and emitted as secondary radiation having a wavelengthrange that is at least partly different, in particular longer, than theprimary radiation. In the case of this so-called partial conversion, thelighting device, in particular the conversion LED, emits in particularan overall radiation composed of the primary radiation and the secondaryradiation. It is thus possible for the lighting device, in particularthe conversion LED, to emit a mixed radiation composed of primaryradiation and secondary radiation.

The fact that the phosphor at least partly converts the electromagneticprimary radiation into an electromagnetic secondary radiation can alsomean that the electromagnetic primary radiation is almost completelyabsorbed by the phosphor and is emitted in the form of anelectromagnetic secondary radiation. This can also be referred to asfull conversion. The emitted radiation or overall radiation of thelighting device, in particular of the conversion LED, in accordance withthis embodiment thus almost completely corresponds to theelectromagnetic secondary radiation. Almost complete conversion shouldbe understood to mean a conversion of more than 90%, in particular morethan 95%. It is thus possible for the lighting device, in particular theconversion LED, to emit predominantly secondary radiation.

In accordance with at least one embodiment, the primary radiation sourceis a layer sequence comprising an active layer configured to emit anelectromagnetic primary radiation during operation of the lightingdevice.

In this context, “layer sequence” should be understood to mean a layersequence comprising more than one layer, for example a sequence of ap-doped and an n-doped semiconductor layer, wherein the layers arearranged one above another and wherein at least one active layer whichemits electromagnetic primary radiation is contained.

The layer sequence can be embodied as an epitaxial layer sequence or asa radiation-emitting semiconductor chip having an epitaxial layersequence, that is to say as an epitaxially grown semiconductor layersequence. In this case, the layer sequence can be embodied for exampleon the basis of InGaAlN. InGaAlN-based semiconductor chips andsemiconductor layer sequences are, in particular, those in which theepitaxially produced semiconductor layer sequence comprises a layersequence composed of different individual layers which contains at leastone individual layer comprising a material from the III-V compoundsemiconductor material system In_(x)Al_(y)Ga_(1-x-y)N where 0≤x≤1, 0≤y≤1and x+y≤1. Semiconductor layer sequences comprising at least one activelayer on the basis of InGaAlN can emit for example electromagneticradiation in an ultraviolet to blue wavelength range.

Besides the active layer, the active semiconductor layer sequence cancomprise further functional layers and functional regions, for instancep- or n-doped charge carrier transport layers, that is to say electronor hole transport layers, undoped or p- or n-doped confinement, claddingor waveguide layers, barrier layers, planarization layers, bufferlayers, protective layers and/or electrodes and combinations thereof.Furthermore, one or more mirror layers can be applied for example on aside of the semiconductor layer sequence facing away from the growthsubstrate. The structures described here, concerning the active layer orthe further functional layers and regions, are known to the personskilled in the art in particular with regard to construction, functionand structure and are therefore not explained in greater detail at thisjuncture.

In one embodiment, the emitted primary radiation of the primaryradiation source or of the active layer of the layer sequence is in thenear UV range to blue range of the electromagnetic spectrum. In thiscase, in the near UV range can mean that the emitted primary radiationhas a wavelength of between 300 nm and 420 nm inclusive. In this case,in the blue range of the electromagnetic spectrum can mean that theemitted primary radiation has a wavelength of between 420 nm and 500 nminclusive, advantageously up to and including 460 nm.

In one embodiment, during operation of the lighting device the activelayer of the layer sequence emits an electromagnetic primary radiationhaving a wavelength of between 300 nm and 500 nm inclusive or between300 nm and 460 nm inclusive, advantageously between 300 nm or 330 nm and450 nm or 440 nm or 430 nm inclusive.

In accordance with at least one embodiment, the primary radiation sourceor the layer sequence has a radiation exit surface, above which theconversion element is arranged.

Here and hereinafter the fact that one layer or one element is arrangedor applied “on” or “above” another layer or another element can mean inthis case that said one layer or said one element is arranged directlyin direct mechanical and/or electrical contact on the other layer or theother element. Furthermore, it can also mean that said one layer or saidone element is arranged indirectly on or above the other layer or theother element. In this case, further layers and/or elements can then bearranged between said one or the other layer or between said one or theother element.

In this case, the radiation exit surface is a main surface of theprimary radiation source or of the layer sequence. The radiation exitsurface extends in particular parallel to a main extension plane of thesemiconductor layers of the layer sequence. By way of example, at least75% or 90% of the primary radiation leaving the layer sequence emergesfrom the layer sequence via the radiation exit surface.

In one embodiment, the conversion element has direct mechanical contactwith the primary radiation source or the layer sequence, in particularwith the radiation exit surface of the primary radiation source or ofthe layer sequence.

In one embodiment, the conversion element is arranged over the wholearea above the primary radiation source or the layer sequence, inparticular the radiation exit surface of the primary radiation source orof the layer sequence.

In one embodiment, the conversion element comprises a matrix material.The phosphor can be distributed in the matrix material; by way ofexample, the phosphor is distributed homogeneously in the matrixmaterial.

The matrix material is transparent both to the primary radiation and tothe secondary radiation and is selected for example from a group ofmaterials consisting of: glasses, silicones, epoxy resins,polysilazanes, polymethacrylates and polycarbonates and combinationsthereof. Transparent is understood to mean that the matrix material isat least partly transmissive to the primary radiation and also to thesecondary radiation.

In accordance with at least one embodiment, MA, MB, MC, MD, TA, TB, TC,TD, TE and TF are the corresponding monovalent, divalent, trivalent,tetravalent, pentavalent or hexavalent cations. In other words, MA andTA have the oxidation number +1, MB and TB have the oxidation number +2,MC and TC have the oxidation number +3, MD and TD have the oxidationnumber +4, TE has the oxidation number +5 and TF has the oxidationnumber +6. XA, XB, XC and XD are, in particular, the anions of thecorresponding elements. In this case, XA advantageously has theoxidation number −1, XB the oxidation number −2, XC, that is to say N,the oxidation number −3 and XD, that is to say C, the oxidation number−4.

WO 2013/175336 A1 describes a new family of red-emitting phosphors whichhave an emission having small values of the full width at half maximum.The phosphors disclosed therein have a proportion of at least 87.5%nitrogen and at most 12.5% oxygen relative to the total amount ofanionic elements of the phosphor. In accordance with WO 2013/175336 A1,a higher oxygen content in the phosphors leads to unstable compounds.Consequently, phosphors having an oxygen content of more than 12.5%could not be isolated.

Here and hereinafter the full width at half maximum is understood tomean the spectral width at the level of half the maximum of the emissionpeak, FWHM for short. The emission peak is understood to mean the peakhaving the maximum intensity.

The inventors of the present disclosure have surprisingly establishedthat a higher oxygen and/or sulfur proportion, that is to say an oxygenand/or sulfur proportion in the phosphor of more than 12.5 mol %relative to the total substance amount of anionic elements, or a lowernitrogen proportion, that is to say a nitrogen proportion in thephosphor of less than 87.5 mol % relative to the total substance amountof anionic elements, leads to very stable and efficient phosphors havinga high quantum efficiency. The phosphors have a high absorptivity in theUV range to green range, in particular between 300 nm and 500 nm orbetween 300 nm and 460 nm, advantageously between 300 nm and 430 nm or300 nm and 450 nm, and can thus be efficiently excited by a primaryradiation in this wavelength range. The primary radiation can beconverted completely (full conversion) or partly (partial conversion)into a radiation of longer wavelength, also called secondary radiation,by the phosphors.

In accordance with at least one embodiment, it advantageously holds truethat: 0≤m<0.75 v or v≥l>0.25 v, 0≤m<0.625 v or v≥l>0.375 v. Particularlyadvantageously: 0≤m<0.5 v or v≥l>0.5 v, 0≤m<0.375 v or v≥l>0.625 v,0≤m<0.25 v or v≥l>0.7 v, 0≤m<0.125 v or v≥l>0.875 v or m=0 or 1=v.

The inventors have discovered that, surprisingly, with increasing oxygenand/or sulfur content or with decreasing nitrogen content, the peakwavelength of the phosphors shifts toward shorter wavelengths andmoreover very stable phosphors result. As a result it is advantageouslypossible to correspondingly set the desired peak wavelength of thephosphor by varying the oxygen or nitrogen content. Moreover, the peakwavelength and/or the full width at half maximum of the phosphor can bevaried by combinations or substitutions of the metals or elements MA,MB, MC, MD, TA, TB, TC, TD, TE, TF, XA, XC, XD and/or XB. A possibilityhas thus been found of providing phosphors which, in terms of theirproperties, in particular the peak wavelength and the full width at halfmaximum, can be adapted in a targeted manner for a correspondingapplication and in this case are surprisingly also still very stable. Inparticular, the phosphors can have very narrow values of the full widthat half maximum, for example below 50 nm, below 30 nm or below 20 nm,which makes the phosphors interesting for many applications, for examplefor backlighting applications.

In the present case, “peak wavelength” denotes the wavelength in theemission spectrum at which the maximum intensity is present in theemission spectrum.

In accordance with at least one embodiment, the following hold true forthe phosphor having the molecular formula (MA)_(a)(MB)_(b)(MC)_(c)(MD)_(d)(TA)_(e)(TB)_(f)(TC)_(g)(TD)_(h)(TE)_(i)(TF)_(j)(XA)_(k)(XB)_(l)(XC)_(m)(XD)_(n):E:

a+b+c+d=1;

e+f+g+h+i+j=4;

k+l+m+n=4;

a+2b+3c+4d+e+2f+3g+4h+5i+6j−k−2l−3m−4n=0 and m<3.5 or l>0.5. This istherefore an electroneutral phosphor.

In accordance with at least one embodiment, it holds true that n=0, k=0,v=4 and m<3.5 and l>0.5. Then the phosphor thus has the followingmolecular formula:(MA)_(a)(MB)_(b)(MC)_(c)(MD)_(d)(TA)_(e)(TB)_(f)(TC)_(g)(TD)_(h)(TE)_(i)(TF)_(j)(XB)_(l)(XC)_(m):E.In this case, MA, MB, MC, MD, TA, TB, TC, TD, TE, TF, XC and XB aredefined as above. In accordance with this embodiment, the phosphorcomprises only nitrogen and oxygen, nitrogen and sulfur or nitrogen,sulfur and oxygen, advantageously only nitrogen and oxygen, as anions.However, this does not exclude the presence of further, includinganionic, elements in the form of impurities. It advantageously holdstrue that m<3.0 and l>1.0; m<2.5 and l>1.5; m<2.0 and l<2.0; m<1.5 andl>2.5; m<1.5 and l>2.5; m<1.0 and l>3.0; m<0.5 and l>3.5 or m=0 and 1=4.

In accordance with at least one embodiment, the phosphor has the generalmolecular formula (MA)_(a)(MB)_(b)(TA)_(e)(TD)_(h)(XB)_(l)(XC)_(m):E.

In this case, the following advantageously hold true:

-   -   MA is selected from a group of monovalent metals which comprises        Li, Na, K, Rb, Cs, Cu, Ag and combinations thereof. Particularly        advantageously, MA is selected from a group of monovalent metals        which comprises Li, Na, K, Rb, Cs and combinations thereof,    -   MB is selected from a group of divalent metals which comprises        Mg, Ca, Sr, Ba, Zn, Mn, Eu, Yb, Ni, Fe, Co and combinations        thereof. Particularly advantageously, MB is selected from a        group of divalent metals which comprises Mn, Eu, Yb and        combinations thereof. Very particularly advantageously, MB=Eu or        a combination of Eu and Mn and/or Yb,    -   TA is selected from a group of monovalent metals which comprises        Li, Na, Cu, Ag and combinations thereof. Particularly        advantageously, TA is selected from a group of monovalent metals        which comprises Li, Na and combinations thereof. Very        particularly advantageously, TA=Li,    -   TD is selected from a group of tetravalent metals which        comprises Si, Ge, Sn, Mn, Ti, Zr, Hf, Ce and combinations        thereof. Particularly advantageously, TD is selected from a        group of tetravalent metals which comprises Si, Ge, Sn, Mn, Ti,        and combinations thereof. Very particularly advantageously,        TD=Si,    -   XB is selected from a group of elements which comprises O, S and        combinations thereof. Particularly advantageously, XB=O,    -   XC=N. The following furthermore hold true:    -   a+b=t,    -   e+h=u,    -   l+m=v,    -   a+2b+e+4h−2l−3m=w    -   0.8≤t≤1    -   3.5≤u≤4    -   3.5≤v≤4    -   (−0.2)≤w≤0.2    -   0≤m<0.875 v and/or v≥1>0.125 v and    -   E=Eu, Ce, Yb and/or Mn, advantageously E=Eu.

In accordance with at least one embodiment, the phosphor has the generalmolecular formula(MA)_(a)(MB)_(b)(TA)_(e)(TD)_(h)(XB)_(l)(XC)_(m):E.In this case, the following hold true:

-   -   MA is selected from a group of monovalent metals which comprises        Li, Na, K, Rb, Cs, Cu, Ag and combinations thereof.        Advantageously, MA is selected from a group of monovalent metals        which comprises Li, Na, K, Rb and combinations thereof,    -   MB is selected from a group of divalent metals which comprises        Mg, Ca, Sr, Ba, Zn, Mn, Eu, Yb, Ni, Fe, Co and combinations        thereof. It is advantageously selected from a group of divalent        metals which comprises Mn, Eu, Yb and combinations thereof.        Particularly advantageously, MB=Eu or a combination of Eu with        Mn and/or Yb,    -   TA is selected from a group of monovalent metals which comprises        Li, Na, Cu, Ag and combinations thereof. Advantageously, TA is        selected from a group of monovalent metals which comprises Li,        Na and combinations thereof. Particularly advantageously, TA=Li,    -   TD is selected from a group of tetravalent metals which        comprises Si, Ge, Sn, Mn, Ti, Zr, Hf, Ce and combinations        thereof. Advantageously, TD is selected from a group of        tetravalent metals which comprises Si, Ge, Sn, Mn, Ti, and        combinations thereof. Particularly advantageously, TD=Si,    -   XB is selected from a group of elements which comprises O, S and        combinations thereof. Advantageously, XB=O.    -   XC=N. The following furthermore hold true:        a+b=1;        e+h=4;        l+m=4;    -   a+2b+e+4h−2l−3m=0 and m<3.5 or l>0.5 and E=Eu, Ce, Yb and/or Mn,        advantageously E=Eu.

In accordance with at least one embodiment, the phosphor has the generalmolecular formula(MA)_(a)(MB)_(b)(TA)_(e)(TC)_(g)(TD)_(h)(XB)_(l)(XC)_(m):E auf, wherein

-   -   MA is selected from a group of monovalent metals which comprises        Li, Na, K, Rb, Cs, Cu, Ag and combinations thereof,    -   MB is selected from a group of divalent metals which comprises        Mg, Ca, Sr, Ba, Zn, Mn, Eu, Yb, Ni, Fe, Co and combinations        thereof,    -   TA is selected from a group of monovalent metals which comprises        Li, Na, Cu, Ag and combinations thereof,    -   TC is selected from a group of trivalent metals which comprises        B, Al, Ga, In, Y, Fe, Cr, Sc, rare earths and combinations        thereof,    -   TD is selected from a group of tetravalent metals which        comprises Si, Ge, Sn, Mn, Ti, Zr, Hf, Ce and combinations        thereof,    -   XB is selected from a group of elements which comprises O, S and        combinations thereof,    -   XC=N    -   a+b=t    -   e+g+h=u    -   l+m=v    -   a+2b+e+3g+4h−2l−3m=w    -   0.8≤t≤1    -   3.5≤u≤4    -   3.5≤v≤4    -   (−0.2)≤w≤0.2 and        E=Eu, Ce, Yb and/or Mn. It advantageously holds true that:        0≤m<0.875 v and/or v≥l>0.125 v. In accordance with this        embodiment, the phosphor comprises only nitrogen and oxygen,        nitrogen and sulfur or nitrogen, sulfur and oxygen,        advantageously only nitrogen and oxygen, as anions.

In accordance with at least one embodiment, the phosphor has the generalmolecular formula(MA)_(a)(MB)_(b)(TA)_(e)(TC)_(g)(TD)_(h)(XB)_(l)(XC)_(m):E auf, wherein

-   -   MA is selected from a group of monovalent metals which comprises        Li, Na, K, Rb, Cs, Cu, Ag and combinations thereof,    -   MB is selected from a group of divalent metals which comprises        Mg, Ca, Sr, Ba, Eu and combinations thereof,    -   TA is selected from a group of monovalent metals which comprises        Li, Na, Cu, Ag and combinations thereof,    -   TC is selected from a group of trivalent metals which comprises        B, Al, Ga and combinations thereof,    -   TD is selected from a group of tetravalent metals which        comprises Si, Ge and combinations thereof,    -   XB=O,    -   XC=N    -   a+b=1    -   e+g+h=4    -   l+m=4    -   a+2b+e+3g+4h−2l−3m=0 and        E=Eu, Ce, Yb and/or Mn. Advantageously, m<3.5 or l>0.5. This is        therefore an electroneutral phosphor comprising only nitrogen        and oxygen as anions.

In accordance with at least one embodiment, the phosphor has the generalmolecular formula (MA)_(a)(MB) b (TA) e (TC)_(g) (TD) h(XB)_(l)(XC)_(m):E, wherein

-   -   MA is selected from a group of monovalent metals which comprises        Li, Na, K and combinations thereof,    -   MB is selected from a group of divalent metals which comprises        Mg, Ca, Sr, Ba, Eu and combinations thereof,    -   TA=Li,    -   TC=Al,    -   TD=Si,    -   XB=O,    -   XC=N    -   a+b=1    -   e+g+h=4    -   l+m=4    -   a+2b+e+3g+4h−2l−3m=0 and E=Eu, Ce, Yb and/or Mn, advantageously        E=Eu. Advantageously, m<3.5 or l>0.5. This is therefore an        electroneutral phosphor comprising only nitrogen and oxygen as        anions. The phosphor contains within its molecular formula at        least Eu, Ce, Yb and/or Mn.

In accordance with at least one embodiment, the phosphor is an oxide,that is to say that only oxygen is present as anionic element in thephosphor. The phosphor then has one of the following general molecularformulae:(MA)₁(TA)₃(TD)₁(XB)₄:E,(MA)₁(TA)_(3-x)(TD)_(1-x)(TB)_(x)(TC)_(x)(XB)₄:E,(MA)_(1-x′)(MB)_(x′)(TA)₃(TD)_(1−x′)(TC)_(x′)(XB)₄:E,(MA)_(1−x″)(MB)_(x)(TA)_(3−x″)(TD)_(1−x″)(TB)_(2x″)(XB)₄:E,(MA)₁(TA)_(3−2z)(TB)_(3z)(TD)_(1−z)(XB)₄:E or(MA)₁(TA)₃(TD)_(1−2z′)(TC)_(z′)(TE)_(z′)(XB)₄:E, whereinXB=O,0≤x≤1, for example x=0, 0.1; 0.2; 0.3; 0.4; 0.5; 0.6; 0.7; 0.8; 0.9 or1, advantageously 0<x<1, for example x=0.1; 0.2; 0.3; 0.4; 0.5; 0.6;0.7; 0.8 or 0.9,0≤x′≤1, for example x′=0, 0.1; 0.2; 0.3; 0.4; 0.5; 0.6; 0.7; 0.8; 0.9 or1, advantageously 0<x′<1, for example x′=0.1; 0.2; 0.3; 0.4; 0.5; 0.6;0.7; 0.8 or 0.9,0≤x″≤1, for example x″=0, 0.1; 0.2; 0.3; 0.4; 0.5; 0.6; 0.7; 0.8; 0.9 or1, advantageously 0<x<1, for example x″=0.1; 0.2; 0.3; 0.4; 0.5; 0.6;0.7; 0.8 or 0.9,0≤z≤1, advantageously z=0, 0.1; 0.2; 0.3; 0.4; 0.5; 0.6; 0.7; 0.8; 0.9or 1, advantageously 0<z<1, for example z=0.1; 0.2; 0.3; 0.4; 0.5; 0.6;0.7; 0.8 or 0.9,0≤z′≤0.5, advantageously 0<z′<0.5, for example z′=0, 0.1; 0.2; 0.3 or0.4,and E is selected from a group comprising Eu, Ce, Yb, Mn andcombinations thereof.

Here and hereinafter E can also be referred to as activator. Theactivator and in particular its surroundings in the host lattice areresponsible for the luminescence, in particular the peak wavelength ofthe emission of the phosphor.

The metals or elements MA, MB, TA, TB, TC, TD, TE and/or XB form in thephosphors in particular the host lattice; in this case, E can partlyreplace lattice sites of the cationic elements MA, MB, TA, TB, TC, TDand/or TE, or occupy interstitial sites. In particular, in this case Eoccupies the lattice sites of MA. For charge balancing, the proportionof the further elements, for example that of TA and/or TD, may change.

In accordance with at least one embodiment, the phosphor is an oxide oroxonitride, advantageously an oxonitride, and therefore has in itsmolecular formula only oxygen or oxygen and nitrogen as anionicelements. In this case, the phosphor can have one of the followinggeneral molecular formulae:(MA)_(1−y)(TB)_(y)(TA)_(3−2y)(TC)_(3y)(TD)_(1−y)(XB)_(4−4y)(XC)_(4y):E,(MA)_(1−y*)(MB)_(y*)(TA)_(3−2y*)(TC)_(3y*)(TD)_(1−y*)(XB)_(4−4y*)(XC)_(4y*):E,(MA)₁(TA)_(3−y′)(TC)_(y′)(TD)₁(XB)_(4−2y′)(XC)_(2y′):E,(MA)₁(TA)_(3−y″)(TB)_(y″)(TD)₁(XB)_(4−y″)(XC)_(y″):E,(MA)_(1−w′″)(MB)_(w′″)(TA)₃(TD)₁(XB)_(4−w′″)(XC)_(w′″):E,(MA)₁(TA)_(3−w′)(TC)_(2w′)(TD)_(1−w′)(XB)_(4−w′)(XC)_(w′):E or(MA)_(1−w″)(MB)_(w″)(TA)_(3−w″)(TD)_(1−w″)(TC)_(2w″)(XB)_(4−2w″)(XC)_(2w″):E,whereinXB=O,0≤y≤1, for example y=0; 0.1; 0.2; 0.3; 0.4; 0.5; 0.6; 0.7; 0.8; 0.9 or1, advantageously 0<y<0.875, for example y=0.1; 0.2; 0.3; 0.4; 0.5; 0.6;0.7 or 0.8, very particularly advantageously 0≤y≤0.4,0<y*<0.875 or advantageously 0<y*≤0.5, particularly advantageously0<y*≤0.3, very particularly advantageously 0<y*≤0.1,0≤y′≤2, for example y′=0, 0.1; 0.2; 0.3; 0.4; 0.5; 0.6; 0.7; 0.8; 0.9;1.0; 1.1; 1.2; 1.3; 1.4; 1.5; 1.6; 1.7; 1.8; 1.9 or 2.0, advantageously0<y′≤1.75, particularly advantageously 0≤y′≤0.9,0≤y″≤3, for example y″=0, 0.1; 0.2; 0.3; 0.4; 0.5; 0.6; 0.7; 0.8; 0.9;1.0; 1.1; 1.2; 1.3; 1.4; 1.5; 1.6; 1.7; 1.8; 1.9; 2.0; 2.1; 2.2; 2.3;2.4; 2.5; 2.6; 2.7; 2.8; 2.9 or 3.0, advantageously 0<y″<3, particularlyadvantageously 0<y″≤1.9,0≤w′″≤1, for example w′″=0, 0.1; 0.2; 0.3; 0.4; 0.5; 0.6; 0.7; 0.8; 0.9or 1, advantageously 0<w′″<1,0≤w′≤1, for example w′=0, 0.1; 0.2; 0.3; 0.4; 0.5; 0.6; 0.7; 0.8; 0.9 or1, advantageously 0<w′<1,0≤w″≤1, for example w″=0, 0.1; 0.2; 0.3; 0.4; 0.5; 0.6; 0.7; 0.8; 0.9 or1, advantageously 0<w″<1, and E is selected from a group which comprisesEu, Ce, Yb, Mn and combinations thereof.

In accordance with at least one embodiment, E is selected from a groupwhich comprises Eu, Ce, Yb, Mn and combinations thereof. In particular,E is Eu³⁺, Eu²⁺, Ce³⁺, Yb³⁺, Yb²⁺ and/or Mn⁴⁺.

The metals or elements MA, MB, TA, TB, TC, TD, XC and/or XB form thehost lattice in the phosphors; in this case, E can partly replacelattice sites of MA, MB, TA, TB, TC and/or TD, advantageously of MA, oroccupy interstitial sites.

By using the activators Eu, Ce, Yb and/or Mn, in particular Eu or Eu incombination with Ce, Yb and/or Mn, it is possible for the color locus ofthe phosphor in the CIE color space, the peak wavelength λpeak thereofor the dominant wavelength λdom thereof, and the full width at halfmaximum to be set particularly well.

The dominant wavelength is a possibility for describing non-spectral(polychromatic) light mixtures by spectral (monochromatic) light thatproduces a similar hue perception. In the CIE color space, the lineconnecting a point for a specific color and the point CIE-x=0.333,CIE-y=0.333 can be extrapolated such that it meets the contour of thespace at two points. The intersection point that is nearer to said colorrepresents the dominant wavelength of the color as wavelength of thepure spectral color at this intersection point. The dominant wavelengthis thus the wavelength that is perceived by the human eye.

In accordance with a further embodiment, the activator E can be presentin mol % amounts of between 0.1 mol % and 20 mol %, 1 mol % and 10 mol%, 0.5 mol % and 5 mol %, 2 mol % and 5 mol %. Excessively highconcentrations of E may lead to a loss of efficiency as a result ofconcentration quenching. Here and hereinafter, mol % indications for theactivator E, in particular Eu, are understood in particular as mol %indications relative to the molar proportions of MA, MB, MC and MD inthe respective phosphor.

In accordance with at least one embodiment, the phosphor has one of thefollowing general molecular formulae:(MA)Li_(3−x)Si_(1−x)Zn_(x)Al_(x)O₄:E;(MA)Li_(3−x)Si_(1−x)Mg_(x)Al_(x)O₄:E;(MA)_(1−x′)Ca_(x′)Li₃Si_(1−x′)Al_(x′)O₄:E;(MA)_(1−x″)Ca_(x″)Li_(3−x″)Si_(1−x″)Mg_(2x″)O₄:E;(MA)Li_(3−2z)Mg_(3z)Si_(1−z)O₄:E;(MA)Li₃Si_(1−2z′)Al_(z′)P_(z′)O₄:E.In particular, MA, E, x, x′, x″, z and z′ are accorded the definitionsdisclosed above.

Proceeding from the phosphor of the molecular formula (MA)Li₃SiO₄:E, inaccordance with at least one embodiment, LiSi can be at least partlyreplaced by ZnAl or MgAl and a phosphor of the formula(MA)Li_(3−x)Si_(1−x)Zn_(x)Al_(x)O₄:E or(MA)Li_(3−x)Si_(1−x)Mg_(x)Al_(x)O₄:E is obtained.

Proceeding from the phosphor of the molecular formula (MA)Li₃SiO₄:E inaccordance with at least one embodiment, (MA)Si can be at least partlyreplaced by CaAl and a phosphor of the formula(MA)_(1−x′)Ca_(x′)Li₃Si_(1−x′)Al_(x′)O₄:E is obtained.

Proceeding from the phosphor of the molecular formula (MA)Li₃SiO₄:E inaccordance with at least one embodiment, (MA)LiSi can be at least partlyreplaced by CaMg₂ and a phosphor of the formula(MA)_(1−x″)Ca_(x″)Li_(3−x″)Si_(1−x″)Mg_(2x″)O₄:E is obtained.

Proceeding from the phosphor of the molecular formula (MA)Li₃SiO₄:E inaccordance with at least one embodiment, Li₂Si can be at least partlyreplaced by Mg₃ and a phosphor of the formula(MA)Li_(3−2z)Mg_(3z)Si_(1−z)O₄:E is obtained.

Proceeding from the phosphor of the molecular formula (MA)Li₃SiO₄:E inaccordance with at least one embodiment, Si₂ can be at least partlyreplaced by AlP and a phosphor of the formula(MA)Li₃Si_(1−2z′)Al_(z′)P_(z′)O₄:E is obtained.

In accordance with at least one embodiment, the phosphor has one of thefollowing general molecular formulae:(MA)_(1−y)Zn_(y)Li_(3−2y)Al_(3y)Si_(1−y)O_(4−4y)N_(4y):E(MA)_(1−y*)Ca_(y*)Li_(3−2y*)Al_(3y*)Si_(1−y*)O_(4−4y*)N_(4y*):E,(MA)_(1−y***)Sr_(y***)Li_(3−2y***)Al_(3y***)Si_(1−y***)O_(4−4y***)N_(4y***):E(MA)_(1−y**)Eu_(y**)Li_(3−2y**)Al_(3y**)Si_(1−y**)O_(4−4y**)N_(4y**):E(MA)Li_(3−y′)Al_(y′)SiO_(4−2y′)N_(2y′):E,(MA)Li_(3−y″)Mg_(y″)SiO_(4−y″)N_(y″):E,(MA)_(1−w′″)Ca_(w′″)Li₃SiO_(4−w′″)N_(w′″):E,(MA)Li_(3−w′)Al_(2w′)Si_(1−w′)O_(4−w)′N_(w′):E,(MA)_(1−w″)Ca_(w″)Li_(3−w″)Si_(1−w″)Al_(2w″)O_(4−2w″)N_(2w″):E.In particular, MA, E, y, y*, y′, y″, w′″, w′ and w″ are accorded thedefinitions disclosed above. It furthermore holds true that 0<y**≤1,advantageously 0<y**<0.875 or 0<y**<0.5, particularly advantageously0.05≤y**≤0.45, very particularly advantageously 0.1≤y**≤0.4,0.15≤y**≤0.35 or 0.2≤y**≤0.3 and 0≤y***≤1, advantageously 0<y***<0.875or 0<y***≤0.5, particularly advantageously 0<y***≤0.3.

Proceeding from the phosphor of the molecular formula (MA)Li₃SiO₄:E inaccordance with at least one embodiment, (MA)Li₃SiO₄ can be at leastpartly replaced by CaLiAl₃N₄ and a phosphor of the formula(MA)_(1−y*)Ca_(y*)Li_(3−2y*)Al_(3y*)Si_(1−y*)O_(4−4y*)N_(4y*):E isobtained. In this case, MA is selected from a group of monovalent metalswhich comprises Li, Na, K, Rb, Cs, Cu, Ag and combinations thereof, andE is selected from a group which comprises Eu, Ce, Yb, Mn andcombinations thereof. Advantageously, MA is selected from a group ofmonovalent metals which comprises Li, Na, K, Rb and combinations thereofand E=Eu. Very advantageously, MA=Na. The phosphor is anoxonitridolithoalumosilicate phosphor. It holds true that 0<y*<0.875,advantageously 0<y*≤0.5, particularly advantageously 0<y*≤0.3, veryparticularly advantageously 0<y*≤0.1. By way of example, it holds truethat y*=0.01; 0.02; 0.03; 0.04 or 0.05.

Proceeding from the phosphor of the molecular formula (MA)Li₃SiO₄:E inaccordance with at least one embodiment, (MA)Li₃SiO₄ can be at leastpartly replaced by SrLiAl₃N₄ and a phosphor of the formula(MA)_(1−y***)Sr_(y***)Li_(3−2y***)Al_(3y***)Si_(1−y***)O_(4−4y***)N_(4y***):Eis obtained. In this case, MA is selected from a group of monovalentmetals which comprises Li, Na, K, Rb, Cs, Cu, Ag and combinationsthereof and E is selected from a group which comprises Eu, Ce, Yb, Mnand combinations thereof, advantageously, E=Eu. Advantageously, MA isselected from a group of monovalent metals which comprises Li, Na, K, Rband combinations thereof. Very advantageously, MA=Na. The phosphor is anoxonitridolithoalumosilicate phosphor. It holds true that 0<y***<0.875,advantageously 0<y***≤0.5, particularly advantageously 0<y***≤0.3. Forexample y***=0.25.

Proceeding from the phosphor of the molecular formula (MA)Li₃SiO₄:E inaccordance with at least one embodiment, (MA)Li₃SiO₄ can be at leastpartly replaced by EuLiAl₃N₄ and a phosphor of the formula(MA)_(1−y**)Eu_(y**)Li_(3−2y**)Al_(3y**)Si_(1−y**)O_(4−4y**)N_(4y**):Eis obtained. In this case, MA is selected from a group of monovalentmetals which comprises Li, Na, K, Rb, Cs, Cu, Ag and combinationsthereof, and E is selected from a group which comprises Eu, Ce, Yb, Mnand combinations thereof; advantageously, E=Eu. Advantageously, MA isselected from a group of monovalent metals which comprises Li, Na, K, Rband combinations thereof. Very advantageously, MA=Na. The phosphor is anoxonitridolithoalumosilicate phosphor. It advantageously holds true that0<y**<0.875 or 0<y**<0.5, particularly advantageously 0.05≤y**≤0.45,very particularly advantageously 0.1≤y**≤0.4, 0.15≤y**≤0.35 or0.2≤y**≤0.3. Surprisingly, despite the in some instances very highproportions of Eu, the phosphor does not exhibit anyconcentration-governed quenching behavior and the associated loss ofefficiency. Despite the high proportion of Eu, the phosphor is thussurprisingly very efficient.

Proceeding from the phosphor of the molecular formula (MA)Li₃SiO₄:E inaccordance with at least one embodiment, LiO₂ can be at least partlyreplaced by AlN₂ and a phosphor of the formula(MA)Li_(3−y′)Al_(y′)SiO_(4−2y′)N_(2y′):E is obtained.

Proceeding from the phosphor of the molecular formula (MA)Li₃SiO₄:E inaccordance with at least one embodiment, LiO can be at least partlyreplaced by MgN and a phosphor of the formula(MA)Li_(3−y″)Mg_(y″)SiO_(4−y″)N_(y″):E is obtained.

Proceeding from the phosphor of the molecular formula (MA)Li₃SiO₄:E inaccordance with at least one embodiment, (MA)O can be at least partlyreplaced by CaN and a phosphor of the formula(MA)_(1−w′″)Ca_(w′″)Li₃SiO_(4−w′″)N_(w′″):E is obtained.

Proceeding from the phosphor of the molecular formula (MA)Li₃SiO₄:E inaccordance with at least one embodiment, LiSiO can be at least partlyreplaced by Al₂N and a phosphor of the formula(MA)Li_(3w′)Al_(2w′)Si_(1−w′)O_(4−w′)N_(w′):E is obtained.

Proceeding from the phosphor of the molecular formula (MA)Li₃SiO₄:E inaccordance with at least one embodiment, (MA)Li₃SiO₂ can be at leastpartly replaced by CaAl₂N₂ and a phosphor of the formula(MA)_(1−w″)Ca_(w″)Li_(3−w″)Si_(1−w″)Al_(2w″)O_(4−2w″)N_(2w″):E isobtained.

In accordance with at least one embodiment, MA is selected from a groupof monovalent metals which comprises Li, Na, K, Rb, Cs and combinationsthereof. By way of example, MA can be chosen as follows: MA=Na, K,(Na,K), (Rb,Li). (Na,K), (Rb,Li) in this case means that a combinationof Na and K or a combination of Rb and Li is present. This choice of MAyields particularly efficient phosphors that are applicable in diverseways.

In accordance with at least one embodiment, the phosphor has one of thefollowing general molecular formulae:NaLi_(3−x)Si_(1−x)Zn_(x)Al_(x)O₄:E,NaLi_(3−x)Si_(1−x)Mg_(x)Al_(x)O₄:E,Na_(1−x′)Ca_(x′)Li₃Si_(1−x′)Al_(x′)O₄:E,Na_(1−x″)Ca_(x″)Li_(3−x″)Si_(1−x″)Mg_(2x″)O₄:E,NaLi_(3−2z)Mg_(3z)Si_(1−z)O₄:E,NaLi₃Si_(1−2z′)Al_(z′)P_(z′)O₄:E.In particular, x, x′, x″, z and z′ are accorded the meanings mentionedabove.

In accordance with at least one embodiment, the phosphor has one of thefollowing general molecular formulae:(Na_(r)K_(1−r))₁Li_(3−x)Si_(1−x)Zn_(x)Al_(x)O₄:E,(Na_(r)K_(1−r))₁Li_(3−x)Si_(1−x)Mg_(x)Al_(x)O₄:E,(Na_(r)K_(1−r))_(1−x′)Ca_(x′)Li₃Si_(1−x′)Al_(x′)O₄:E,(Na_(r)K_(1−r))_(1−x″)Ca_(x″)Li_(3−x″)Si_(1−x″)Mg_(2x″)O₄:E,(Na_(r)K_(1−r))₁Li_(3−2z)Mg_(3z)Si_(1−z)O₄:E,(Na_(r)K_(1−r))₁Li₃Si_(1−2z′)Al_(z′)P_(z′)O₄:E, wherein0≤r≤1, for example r=0; 0.05; 0.1; 0.15; 0.2; 0.25; 0.3; 0.35, 0.4;0.45; 0.5; 0.55; 0.6; 0.65; 0.7; 0.75; 0.8; 0.85; 0.9; 0.95; 1.0.Advantageously, 0≤r≤0.1 or 0.1<r≤0.4 or 0.4<r≤1.0; particularlyadvantageously r=0, 0.125, 0.25, 0.5 or 1.0. In particular, x, x′, x″, zand z′ are accorded the meanings mentioned above.

In accordance with at least one embodiment, the phosphor has one of thefollowing general molecular formulae:(Rb_(r′)Li_(1−r′))₁Li_(3−x)Si_(1−x)Zn_(x)Al_(x)O₄:E,(Rb_(r′)Li_(1−r′))₁Li_(3−x)Si_(1−x)Mg_(x)Al_(x)O₄:E,(Rb_(r′)Li_(1−r′))_(1−x′)Ca_(x′)Li₃Si_(1−x′)Al_(x′)O₄:E,(Rb_(r′)Li_(1−r′))_(1−x″)Ca_(x″)Li_(3−x″)Si_(1−x″)Mg_(2x″)O₄:E,(Rb_(r′)Li_(1−r′))₁Li_(3−2z)Mg_(3z)Si_(1−z)O₄:E,(Rb_(r′)Li_(1−r′))₁Li₃Si_(1−2z′)Al_(z′)P_(z′)O₄:E, wherein0≤r′≤1, for example r′=0; 0.05; 0.1; 0.15; 0.2; 0.25; 0.3; 0.35, 0.4;0.45; 0.5; 0.55; 0.6; 0.65; 0.7; 0.75; 0.8; 0.85; 0.9; 0.95; 1.0,advantageously 0.25≤r′≤0.75, particularly advantageously 0.4≤r′≤0.6,very particularly advantageously r′=0.5. In particular, x, x′, x″, z andz′ are accorded the meanings mentioned above.

In accordance with at least one embodiment, the phosphor has one of thefollowing general molecular formulae:(Na_(r)K_(1−r))_(1−y*)Ca_(y*)Li_(3−2y*)Al_(3y*)Si_(1−y)O_(4−4y*)N_(4y*):E,(Na_(r)K_(1−r))Li_(3−y′)Al_(y′)SiO_(4−2y′)N_(2y′):E,(Na_(r)K_(1−r))Li_(3−y″)Mg_(y″)SiO_(4−y″)N_(y″):E,(Na_(r)K_(1−r))_(1−w′″)Ca_(w′″)Li₃SiO_(4−w′″)N_(w):E,(Na_(r)K_(1−r))Li_(3−w′)Al_(2w′)Si_(1−w′)O_(4−w′)N_(w′):E,(Na_(r)K_(1−r))_(1−w″)Ca_(w″)Li_(3−w″)Si_(1−w″)Al_(2w″)O_(4−2w″)N_(2w″):E,wherein0≤r≤1, for example r=0; 0.05; 0.1; 0.15; 0.2; 0.25; 0.3; 0.35, 0.4;0.45; 0.5; 0.55; 0.6; 0.65; 0.7; 0.75; 0.8; 0.85; 0.9; 0.95; 1.0.Advantageously, 0≤r≤0.1 or 0.1<r≤0.4 or 0.4<r≤1.0; particularlyadvantageously r=0, 0.25, 0.5 or 1.0. In particular, y*, y′, y″, w′″, w′and w″ are accorded the meanings mentioned above.

In accordance with at least one embodiment, the phosphor has one of thefollowing general molecular formulae:(Rb_(r′)Li_(1−r′))_(1−y*)Ca_(y*)Li_(3−2y*)Al_(3y*)Si_(1−y*)N_(4y*):E,(Rb_(r′)Li_(1−r′))Li_(3−y′)Al_(y′)SiO_(4−2y′)N_(2y′):E,(Rb_(r′)Li_(1−r′))Li_(3−y″)Mg_(y″)SiO_(4−y″)N_(y″):E,(Rb_(r′)Li_(1−r′))_(1−w′″)Ca_(w′″)Li₃SiO_(4−w′″)N_(w):E,(Rb_(r′)Li_(1−r′))Li_(3−w′)Al_(2w′)Si_(1−w′)O_(4−w′)N_(w′):E,(Rb_(r′)Li_(1−r′))_(1−w″)Ca_(w″)Li_(3−w″)Si_(1−w″)Al_(2w″)O_(4−2w″)N_(2w″):E,wherein0≤r′≤1, for example r′=0; 0.05; 0.1; 0.15; 0.2; 0.25; 0.3; 0.35, 0.4;0.45; 0.5; 0.55; 0.6; 0.65; 0.7; 0.75; 0.8; 0.85; 0.9; 0.95; 1.0,advantageously 0.25≤r′≤0.75, particularly advantageously 0.4≤r′≤0.6,very particularly advantageously r′=0.5. In particular, y*, y′, y″, w′″,w′ and w″ are accorded the meanings mentioned above.

In accordance with at least one embodiment, the phosphor has one of thefollowing general molecular formulae:Na_(1−y*)Ca_(y*)Li_(3−2y*)Al_(3y*)Si_(1−y*)O_(4−4y*)N_(4y*):E,NaLi_(3−y′)Al_(y′)SiO_(4−2y′)N_(2y′):E,NaLi_(3−y″)Mg_(y″)SiO_(4−y″)N_(y″):E,Na_(1−w′″)Ca_(w′″)Li₃SiO_(4−w′″)N_(w):E,NaLi_(3−w′)Al_(2w′)Si_(1−w′)O_(4−w′)N_(w′):E,Na_(1−w″)Ca_(w″)Li_(3−w″)Si_(1−w″)Al_(2w″)O_(4−2w″)N_(2w″):E.In particular, y*, y′, y″, w′″, w′ and w″ are accorded the meaningsmentioned above.

In accordance with at least one embodiment, the phosphor has the generalmolecular formula (MA)₁(TA)₃(TD)₁(XB)₄:E. In this case, MA is selectedfrom a group of monovalent metals which comprises Li, Na, K, Rb, Cs, Cu,Ag and combinations thereof. Advantageously, MA is selected from a groupof monovalent metals which comprises Li, Na, K, Rb, Cs and combinationsthereof. TA is selected from a group of monovalent metals whichcomprises Li, Na, Cu, Ag and combinations thereof. TD is selected from agroup of tetravalent metals which comprises Si, Ge, Sm, Mn, Ti, Zr, Hf,Ce and combinations thereof. XB is selected from a group of elementswhich comprises O, S and combinations thereof. E is selected from agroup which comprises Eu, Ce, Yb, Mn and combinations thereof;advantageously, E=Eu. In particular, E occupies the lattice sites of MAor interstitial sites. For charge balancing, in this case the proportionof the further elements, for example that of TA and/or TD, may change.By way of example, E=Eu²⁺ and replaces MA⁺ in the molecular formula; thecharge balancing is effected by changing the proportion of TA and/or TD.

In accordance with at least one embodiment, the phosphor has the generalmolecular formula (MA)₁(TA)₃(TD)₁(XB)₄:E. In this case, MA is selectedfrom a group of monovalent metals which comprises Li, Na, K, Rb, Cs andcombinations thereof. TA=Li, TD=Si, XB=O and E is selected from a groupwhich comprises Eu, Ce, Yb, Mn and combinations thereof. Itadvantageously holds true that: E=Eu or a combination of Eu with Ce, Yband/or Mn.

Surprisingly, it has been found that the properties of the phosphor, inparticular with regard to the peak wavelength and the full width at halfmaximum, can be changed considerably by varying the composition of MA.Moreover, the phosphors have a high absorptivity of primary radiation inthe range of 300 nm to 460 nm or 300 nm to 500 nm, in particular between300 nm and 450 nm or 300 nm and 430 nm.

By way of example, the phosphor of the formula NaLi₃SiO₄:Eu, uponexcitation with a primary radiation having a wavelength of 400 nm, emitsin the blue spectral range of the electromagnetic spectrum and exhibitsa narrowband emission, that is to say an emission having a small fullwidth at half maximum. By contrast, upon excitation with a primaryradiation having a wavelength of 400 nm, the phosphor of the formulaKLi₃SiO₄:Eu exhibits very broadband emission from the blue to redspectral range, thus giving rise to a white-colored luminous impression.The phosphors of the formula (Na_(0.5)K_(0.5)) Li₃SiO₄:Eu,(Rb_(0.25)Na_(0.75)) Li₃SiO₄:Eu, (Cs_(0.25)Na_(0.5)K_(0.25)) Li₃SiO₄:Eu,(Rb_(0.25)Na_(0.5)K_(0.25)) Li₃SiO₄:Eu and(Cs_(0.25)Na_(0.25)Rb_(0.25)Li_(0.25)) Li₃SiO₄:Eu exhibit narrowbandemission in the blue-green spectral range of the electromagneticspectrum and the phosphors of the formula (Rb_(0.5)Li_(0.5)) Li₃SiO₄:Eu,(Rb_(0.5)Na_(0.5)) Li₃SiO₄:Eu, (Na_(0.25)K_(0.75)) Li₃SiO₄:Eu,(Na_(0.25)K_(0.50)Li_(0.25)) Li₃SiO₄:Eu and(Cs_(0.25)Na_(0.25)K_(0.25)Li_(0.25)) Li₃SiO₄:Eu exhibit narrowbandemission in the green spectral range of the electromagnetic spectrum.Upon excitation with a primary radiation having a wavelength of 460 nm,the phosphor of the formula Na_(0.125)K_(0.875)Li₃SiO₄:Eu has a band inthe yellow-orange range. Besides the latter,Na_(0.125)K_(0.875)Li₃SiO₄:Eu exhibits a further emission peak havinghigh intensity in the blue-green range.

The properties of the phosphors are presented in the table below:

λ_(prim) λ_(peak) λ_(dom) FWHM NaLi₃SiO₄:Eu 400 nm 469 nm 473 nm 32 nmKLi₃SiO₄:Eu 400 nm 616 nm 585 nm 143 nm  (Na_(0.5)K_(0.5))Li₃SiO₄:Eu 400nm 486 nm 493 nm 19.2 nm   (Rb_(0.5)Li_(0.5))Li₃SiO₄:Eu 400 nm 528 nm538.7 nm   42.8 nm   (Na_(0.25)K_(0.75))Li₃SiO₄:Eu 400 nm 529 nm 541.4nm   45 nm (Na_(0.25)K_(0.5)Li_(0.25))Li₃SiO₄:Eu 460 nm 532 nm 540.3nm   45.6 nm   (Rb_(0.5)Na_(0.5))Li₃SiO₄:Eu 460 nm 528 nm 533 nm 43.3nm   (Rb_(0.25)Na_(0.75))Li₃SiO₄:Eu 400 nm 473 nm 476 nm 22.2 nm  (Cs_(0.25)Na_(0.25)K_(0.25)Li_(0.25))Li₃SiO₄:Eu 400 nm 530 nm 532 nm 46nm (Cs_(0.25)Na_(0.5)K_(0.25))Li₃SiO₄:Eu 400 nm 486 nm 497 nm 26 nm(Rb_(0.25)Na_(0.5)K_(0.25))Li₃SiO₄:Eu 400 nm 480 nm 490 nm 27 nm(Cs_(0.25)Na_(0.25)Rb_(0.25)Li_(0.25))Li₃SiO₄:Eu 400 nm 473 nm 489 nm 24nm Na_(0.125)K_(0.875)Li₃SiO₄:Eu 460 nm 516 nm 554 nm 60 nm

By virtue of the different emission properties, the phosphors aresuitable for a wide variety of applications.

The blue or blue-green spectral range is understood to mean the range ofthe electromagnetic spectrum between 420 nm and 520 nm.

The green spectral range is understood to mean the range of theelectromagnetic spectrum between 520 nm and 580 nm inclusive.

The red spectral range is understood to mean the range of theelectromagnetic spectrum between 630 nm and 780 nm.

The yellow or yellow-orange spectral range is understood to mean therange of the electromagnetic spectrum between 580 nm and 630 nm.

In accordance with at least one embodiment, the phosphor has the generalmolecular formula (Na_(r)K_(1−r))₁(TA)₃(TD)₁(XB)₄:E, where 0≤r≤1, forexample r=0; 0.05; 0.1; 0.125; 0.15; 0.2; 0.25; 0.3; 0.35, 0.4; 0.45;0.5; 0.55; 0.6; 0.65; 0.7; 0.75; 0.8; 0.85; 0.9; 0.95; 1.0.Advantageously, 0≤r≤0.1 or 0.1<r≤0.4 or 0.4<r≤1.0; particularlyadvantageously r=0, 0.125, 0.25, 0.5 or 1.0. Advantageously, TA=Li,TD=Si, XB=O and E=Eu, Ce, Yb and/or Mn, advantageously E=Eu.Surprisingly, the properties of the phosphor, in particular the peakwavelength and the full width at half maximum, change upon variation ofthe proportions of Na and K in the phosphor. As a result, a wide varietyof applications are usable by virtue of these phosphors.

In accordance with at least one embodiment, the phosphor(Na_(r)K_(1−r))₁(TA)₃(TD)₁(XB)₄:E or (Na_(r)K_(1−r)) Li₃SiO₄:Ecrystallizes in a tetragonal, monoclinic or triclinic crystal system, inparticular in a tetragonal or triclinic crystal system. Advantageously,the phosphor in accordance with this embodiment crystallizes in thespace group I4₁/a, I4/m or P-1. Particularly advantageously, thephosphor in accordance with this embodiment crystallizes in a tetragonalcrystal system with the space group I4₁/a or I4/m or in a tricliniccrystal system with the space group P-1.

In accordance with at least one embodiment, the phosphor has the formula(Na_(r)K_(1−r))₁(TA)₃(TD)₁(XB)₄:E where 0.4<r≤1, advantageously0.45<r≤1, very particularly advantageously r=0.5 or 1. Advantageously,TA=Li, TD=Si, XB=O and E=Eu, Ce, Yb and/or Mn, and the phosphor has theformula (Na_(r)K_(1-r))Li₃SiO₄:E. Advantageously, it holds true thatE=Eu. By way of example, the phosphor has the formula NaLi₃SiO₄:Eu or(Na_(0.5)K_(0.5))Li₃SiO₄:Eu. The peak wavelength of the phosphor is inthe blue spectral range, in particular in the range between 450 nm and500 nm.

The phosphor (Na_(r)K_(1−r))₁(TA)₃(TD)₁(XB)₄:E or (Na_(r)K_(1−r))Li₃SiO₄:E where 0.4<r≤1, for example NaLi₃SiO₄:Eu or(Na_(0.5)K_(0.5))Li₃SiO₄:Eu, is suitable in particular for use inconversion LEDs which emit white radiation. To that end, the phosphorcan be combined with a red and green phosphor.

Moreover, the phosphor (Na_(r)K₁-)₁(TA)₃(TD)₁(XB)₄:E or (Na_(r)K_(1-r))Li₃SiO₄:E where 0.4<r≤1, in particular (Na_(0.5)K_(0.5))Li₃SiO₄:Eu, issuitable for use in lighting devices such as conversion LEDs which emita blue radiation.

In accordance with at least one embodiment, the phosphor has the formula(Na_(r)K_(1−r))₁(TA)₃(TD)₁(XB)₄:E where 0.2<r≤0.4, advantageously0.2<r≤0.3, very particularly advantageously r=0.25. Advantageously,TA=Li, TD=Si and XB=O and the phosphor has the formula(Na_(r)K_(1−r))Li₃SiO₄:E. E is selected from a group which comprises Eu,Mn, Ce, Yb and combinations thereof; advantageously, E=Eu. By way ofexample, the phosphor has the formula (Na_(0.25)K_(0.75)) Li₃SiO₄:Eu.The peak wavelength of the phosphor is in the green spectral range, inparticular.

The phosphor (Na_(r)K_(1−r))₁(TA)₃(TD)₁(XB)₄:E or(Na_(r)K_(1−r))Li₃SiO₄:E where 0.2<r≤0.4, advantageously 0.2<r≤0.4,particularly advantageously 0.2<r≤0.3, very particularly advantageouslyr=0.25, is suitable in particular for use in conversion LEDs for thebacklighting of displays.

Moreover, the phosphor (Na_(r)K_(1−r))₁(TA)₃(TD)₁(XB)₄:E or(Na_(r)K_(1-r))Li₃SiO₄:E where 0.2<r≤0.4, advantageously 0.2<r≤0.4, inparticular (Na_(0.25)K_(0.75))Li₃SiO₄:Eu, is suitable for use inlighting devices such as conversion LEDs which emit a green radiation.

In accordance with at least one embodiment, the phosphor has the formula(Na_(r)K_(1−r))₁(TA)₃(TD)₁(XB)₄:E where 0.05<r≤0.2, advantageously0.1<r≤0.2. Advantageously, TA=Li, TD=Si and XB=O and the phosphor hasthe formula (Na_(r)K_(1−r))Li₃SiO₄:E. E is selected from a group whichcomprises Eu, Mn, Ce, Yb and combinations thereof; advantageously, E=Eu.By way of example, the phosphor is Na_(0.125)K_(0.875)Li₃SiO₄:Eu.

Surprisingly, the phosphor of the formula(Na_(r)K_(1-r))₁(TA)₃(TD)₁(XB)₄:E or (Na_(r)K_(1−r))Li₃SiO₄:E where0.05<r≤0.2 has a wide emission band. In particular, besides the bandhaving the highest intensity (=peak wavelength), the phosphor has afurther emission peak, which has an intensity of similar magnitude tothat of the emission peak at the peak wavelength.

The phosphor (Na_(r)K_(1−r))₁(TA)₃(TD)₁(XB)₄:E or (Na_(r)K_(1−r))Li₃SiO₄:E where 0.05<r≤0.2, advantageously 0.1<r≤0.2, in particularNa_(0.125)K_(0.875)Li₃SiO₄:Eu, is suitable for example for use inlighting devices such as conversion LEDs which emit white radiation. Byvirtue of the wide emission, in particular the two emission peaks in theblue or blue-green range and in the yellow-orange range, the phosphorcan advantageously be used as sole phosphor in a lighting device such asa conversion LED. In particular, with such a conversion LED it ispossible to generate a white overall radiation having color temperaturesabove 8000 K and a high color rendering index and great color spacecoverage, which can be used in particular for general lighting andbacklighting of displays.

In accordance with at least one embodiment, the phosphor has the formula(Na_(r)K_(1−r))₁(TA)₃(TD)₁(XB)₄:E where 0≤r≤0.05, advantageously r=0.Advantageously, TA=Li, TD=Si and XB=O and the phosphor has the formula(Na_(r)K_(1−r))Li₃SiO₄:E. E is selected from a group which comprises Eu,Mn, Ce, Yb and combinations thereof, advantageously, E=Eu. By way ofexample, the phosphor is KLi₃SiO₄:Eu. The phosphor exhibits verybroadband emission from the blue to red spectral range, thus giving riseto a white luminous impression.

The phosphor (Na_(r)K_(1−r))₁(TA)₃(TD)₁(XB)₄:E or(Na_(r)K_(1−r))Li₃SiO₄:E where 0≤r≤0.05, in particular KLi₃SiO₄:Eu, issuitable for example for use in lighting devices such as conversion LEDswhich emit white radiation. As a result of the wide emission of thephosphor, the latter can advantageously be used as sole phosphor in alighting device such as a conversion LED.

In accordance with at least one embodiment, the phosphor has the generalmolecular formula (Rb_(r′)Li_(1−r′))₁(TA)₃(TD)₁(XB)₄:E, wherein 0≤r′≤1,for example r′=0; 0.05; 0.1; 0.15; 0.2; 0.25; 0.3; 0.35, 0.4; 0.45; 0.5;0.55; 0.6; 0.65; 0.7; 0.75; 0.8; 0.85; 0.9; 0.95; 1.0, advantageously0.25≤r′≤0.75, particularly advantageously 0.4≤r′≤0.6, very particularlyadvantageously r′=0.5. Advantageously, TA=Li, TD=Si and XB=O and thephosphor has the formula (Rb_(r′)Li_(1−r′))Li₃SiO₄:E. E is selected froma group which comprises Eu, Mn, Ce, Yb and combinations thereof;advantageously, E=Eu. It has been found that these phosphors have asmall full width at half maximum and are applicable in diverse ways.

In accordance with at least one embodiment, the phosphor has the generalmolecular formula (K,Na,Li,Cs)₁(TA)₃(TD)₁(XB)₄:E, wherein K, Na, Li andCs are contained in the phosphor. Advantageously, TA=Li, TD=Si and XB=Oand the phosphor has the formula (K,Na,Li,Cs)Li₃SiO₄:E. E is selectedfrom a group which comprises Eu, Mn, Ce, Yb and combinations thereof;advantageously, E=Eu. Particularly advantageously, the phosphor has theformula (Cs_(0.25)Na_(0.25)K_(0.25)Li_(0.25)) (TA)₃(TD)₁(XB)₄:E or(Cs_(0.25)Na_(0.25)K_(0.25)Li_(0.25))Li₃SiO₄:E. The peak wavelength ofthe phosphor is in the green spectral range, in particular, and has afull width at half maximum of less than 50 nm.

In accordance with at least one embodiment, the phosphor has the generalmolecular formula (Rb,Na,Li,Cs)₁(TA)₃(TD)₁(XB)₄:E, wherein Rb, Na, Liand Cs are contained in the phosphor.

Advantageously, TA=Li, TD=Si and XB=O and the phosphor has the formula(Rb,Na,Li,Cs) Li₃SiO₄:E. E is selected from a group which comprises Eu,Mn, Ce, Yb and combinations thereof; advantageously, E=Eu. Particularlyadvantageously, the phosphor has the formula(Cs_(0.25)Na_(0.25)Rb_(0.25)Li_(0.25)) (TA)₃(TD)₁(XB)₄:E or(Cs_(0.25)Na_(0.25)Rb_(0.25)Li_(0.25))Li₃SiO₄:E. The peak wavelength ofthe phosphor is in the blue spectral range, in particular, and has afull width at half maximum of less than 30 nm.

In accordance with at least one embodiment, the phosphor has the generalmolecular formula (Cs,Na,K)₁(TA)₃(TD)₁(XB)₄:E, wherein Na, K and Cs arecontained in the phosphor. Advantageously, TA=Li, TD=Si and XB=O and thephosphor has the formula (Cs,Na,K)Li₃SiO₄:E. E is selected from a groupwhich comprises Eu, Mn, Ce, Yb and combinations thereof; advantageously,E=Eu. Particularly advantageously, the phosphor has the formula(Cs_(0.25)Na_(0.50)K_(0.25)) (TA)₃(TD)₁(XB)₄:E or(Cs_(0.25)Na_(0.50)K_(0.25))Li₃SiO₄:E. The peak wavelength of thephosphor is in the blue spectral range, in particular, and has a fullwidth at half maximum of less than 30 nm.

In accordance with at least one embodiment, the phosphor has the generalmolecular formula (Rb,Na,K)₁(TA)₃(TD)₁(XB)₄:E, wherein Na, K and Rb arecontained in the phosphor. Advantageously, TA=Li, TD=Si and XB=O and thephosphor has the formula (Rb,Na,K) Li₃SiO₄:E. E is selected from a groupwhich comprises Eu, Mn, Ce, Yb and combinations thereof; advantageously,E=Eu. Particularly advantageously, the phosphor has the formula(Rb_(0.25)Na_(0.50)K_(0.25)) (TA)₃(TD)₁(XB)₄:E or(Rb_(0.25)Na_(0.50)K_(0.25)) Li₃SiO₄:E. The peak wavelength of thephosphor is in the blue spectral range, in particular, and has a fullwidth at half maximum of less than 30 nm.

The phosphors (Rb,Na,Li,Cs)₁(TA)₃(TD)₁(XB)₄:E,(Cs,Na,K)₁(TA)₃(TD)₁(XB)₄:E and (Rb,Na,K)₁(TA)₃(TD)₁(XB)₄:E are suitablein particular for use in conversion LEDs which emit white radiation. Tothat end, the phosphor can be combined in each case with a red and greenphosphor. Moreover, these phosphors are suitable for use in lightingdevices such as conversion LEDs which emit a blue radiation.

In accordance with at least one embodiment, the phosphor(Rb,Na,Li,Cs)₁(TA)₃(TD)₁(XB)₄:E, (K,Na,Li,Cs)₁(TA)₃(TD)₁(XB)₄:E,(Rb,Na,K)₁(TA)₃(TD)₁(XB)₄:E, (Cs,Na,K) (TA)₃(TD)₁(XB)₄:E, (K,Na,Li,Cs)Li₃SiO₄:E, (Rb,Na,Li,Cs) Li₃SiO₄:E, (Rb,Na,K) Li₃SiO₄:E or(Cs,Na,K)Li₃SiO₄:E crystallizes in a tetragonal crystal system.Advantageously, the phosphor in accordance with this embodimentcrystallizes in the space group I4/m. Particularly advantageously, thephosphor in accordance with this embodiment crystallizes in a tetragonalcrystal system with I4/m.

In accordance with at least one embodiment, the phosphor has the generalmolecular formula(K_(1−r″−r′″)Na_(r″)Li_(r′″))₁(TA)₃(TD)₁(XB)₄:E,wherein 0<r″<0.5 and 0<r′″<0.5, for example r″=0.05; 0.1; 0.15; 0.2;0.25; 0.3; 0.35, 0.4; 0.45 and r″′=0.05; 0.1; 0.15; 0.2; 0.25; 0.3;0.35, 0.4; 0.45. Advantageously, 0.1<r′<0.4 and 0.1<r′″<0.4,particularly advantageously 0.2<r″<0.3 and 0.2<r′″<0.3. Advantageously,TA=Li, TD=Si and XB=O and the phosphor has the formula(K_(1−r″-r′″)Na_(r″)Li_(r′″))₁Li₃SiO₄:E. E is selected from a groupwhich comprises Eu, Mn, Ce, Yb and combinations thereof; advantageously,E=Eu. Surprisingly, the properties of the phosphor, in particular thepeak wavelength and the full width at half maximum, change uponvariation of the proportions of Na, Li and K in the phosphor.

As a result, these phosphors can be used in a wide variety ofapplications. By way of example, the phosphor has the formula(K_(0.5)Na_(0.25)Li_(0.25))Li₃SiO₄:Eu. The peak wavelength of thephosphor is in the green spectral range, in particular, and has a fullwidth at half maximum of less than 50 nm.

In accordance with at least one embodiment, the phosphor(K_(1-r″-r′″)Na_(r″)Li_(r′″))₁ (TA)₃(TD)₁(XB)₄:E or(K_(1−r″-r′″)Na_(r″)Li_(r′″))₁Li₃SiO₄:E crystallizes in a tetragonal ormonoclinic crystal system. Advantageously, the phosphor in accordancewith this embodiment crystallizes in the space group I4/m or C2/m.Particularly advantageously, the phosphor in accordance with thisembodiment crystallizes in a tetragonal crystal system with the spacegroup I4/m or in a monoclinic crystal system with the space group C2/m,particularly advantageously in a monoclinic crystal system with thespace group C2/m.

In accordance with at least one embodiment, the phosphor has the generalmolecular formula (Rb_(r*)Na_(1−r*))₁(TA)₃(TD)₁(XB)₄:E, wherein 0<r*<1,for example r*=0.05; 0.1; 0.15; 0.2; 0.25; 0.3; 0.35, 0.4; 0.45; 0.5;0.55; 0.6; 0.65; 0.7; 0.75; 0.8; 0.85; 0.9; 0.95. Advantageously, TA=Li,TD=Si and XB=O and the phosphor has the formula(Rb_(r*)Na_(1−r*))Li₃SiO₄:E. E is selected from a group which comprisesEu, Mn, Ce, Yb and combinations thereof; advantageously E=Eu.

In accordance with at least one embodiment, the phosphor(Rb_(r*)Na_(1−r*))₁(TA)₃(TD)₁(XB)₄:E or (Rb_(r*)Na_(1−r*)) Li₃SiO₄:Ecrystallizes in a tetragonal or monoclinic crystal system.Advantageously, the phosphor in accordance with this embodimentcrystallizes in the space group I4/m or C2/m. Particularlyadvantageously, the phosphor in accordance with this embodimentcrystallizes in a tetragonal crystal system with the space group I4/m orin a monoclinic crystal system with the space group C2/m.

In accordance with at least one embodiment, the phosphor has the generalmolecular formula (Rb_(r*)Na_(1−r*))₁(TA)₃(TD)₁(XB)₄:E, wherein0.4≤r*<1.0, advantageously 0.4≤r*<0.875 or 0.4≤r*≤0.75, particularlyadvantageously 0.4≤r*≤0.6 very particularly advantageously r*=0.5.Advantageously, TA=Li, TD=Si and XB=O and the phosphor has the formula(Rb_(r*)Na_(1-r*))Li₃SiO₄:E. E is selected from a group which comprisesEu, Mn, Ce, Yb and combinations thereof; advantageously E=Eu. By way ofexample, the phosphor has the formula (Rb_(0.5)Na_(0.5))Li₃SiO₄:Eu. Thepeak wavelength of the phosphor is in the green spectral range, inparticular, and has a full width at half maximum of between 42 and 44nm.

In accordance with at least one embodiment, the phosphor has the generalmolecular formula (Rb_(r*)Na_(1−r*))₁(TA)₃(TD)₁(XB)₄:E, wherein0<r*<0.4, for example r*=0.05; 0.1; 0.15; 0.2; 0.25; 0.3; 0.35,advantageously 0.1≤r*≤0.35, particularly advantageously 0.2≤r*≤0.3, veryparticularly advantageously r*=0.25. Advantageously, TA=Li, TD=Si andXB=O and the phosphor has the formula (Rb_(r*)Na_(1−r*))Li₃SiO₄:E. E isselected from a group which comprises Eu, Mn, Ce, Yb and combinationsthereof; advantageously E=Eu. The peak wavelength of the phosphor isadvantageously in the blue spectral range and has a full width at halfmaximum of between 20 and 24 nm.

The phosphor (Rb_(r*)Na_(1−r*))₁(TA)₃(TD)₁(XB)₄:E or(Rb_(r*)Na_(1−r*))Li₃SiO₄:E where 0<r*<0.4, advantageously 0.1≤r*≤0.35,particularly advantageously 0.2≤r*≤0.3, very particularly advantageouslyr*=0.25, is suitable in particular for use in conversion LEDs which emitwhite radiation. To that end, the phosphor can be combined with a redand green phosphor.

Moreover, the phosphor (Rb_(r*)Na_(1−r*))₁(TA)₃(TD)₁(XB)₄:E or(Rb_(r*)Na_(1-r*))Li₃SiO₄:E where 0<r*<0.4, advantageously 0.1≤r*≤0.35,particularly advantageously 0.2≤r*≤0.3, very particularly advantageouslyr*=0.25, is suitable for use in lighting devices such as conversion LEDswhich emit a blue radiation.

In accordance with at least one embodiment, the phosphor has the formula(Na_(r)K_(1−r))₁(TA)₃(TD)₁(XB)₄:E or (Na_(r)K_(1−r))Li₃SiO₄:E where0.2<r≤0.4, advantageously 0.2<r≤0.3, particularly advantageously r=0.25or

(Rb_(r′)Li_(1−r′))₁(TA)₃(TD)₁(XB)₄:E or (Rb_(r′)Li_(1−r′))Li₃SiO₄:Ewhere 0≤r′≤1, advantageously 0.25≤r′≤0.75, particularly advantageously0.4≤r′≤0.6. Advantageously, TA=Li, TD=Si and XB=O. The peak wavelengthof the phosphor is in the green spectral range, in particular, and has afull width at half maximum of less than 50 nm.

Surprisingly, the phosphors according to the present disclosure(Na_(r)K_(1−r))₁(TA)₃(TD)₁(XB)₄:E where 0.2<r≤0.4,(Rb_(r′)Li_(1−r′))₁(TA)₃(TD)₁(XB)₄:E where 0≤r′≤1,(K_(1−r″-r′″)Na_(r″)Li_(r′″))₁(TA)₃(TD)₁(XB)₄:E where 0<r″<0.5 and0<r′″<0.5, (K,Na,Li,Cs) (TA)₃(TD)₁(XB)₄:E, and(Rb_(r*)Na_(1-r*))₁(TA)₃(TD)₁(XB)₄:E where 0.4≤r*<1.0, for example(Rb_(0.5)Li_(0.5)) Li₃SiO₄:Eu, (Na_(0.25)K_(0.75)) Li₃SiO₄:Eu,(Na_(0.25)K_(0.50)Li_(0.25)) Li₃SiO₄:Eu,(Cs_(0.25)Na_(0.25)K_(0.25)Li_(0.25)) Li₃SiO₄:Eu and (Rb_(0.5)Na_(0.5))Li₃SiO₄:Eu, have a peak wavelength in the green spectral range and avery small full width at half maximum and are therefore suitable inparticular for white-emitting lighting devices such as, for example,white-emitting conversion LEDs in conjunction with a semiconductor chipthat emits a blue primary radiation and with a red phosphor forbacklighting applications in particular for display elements such asdisplays. Advantageously, a particularly large bandwidth of colors canbe achieved with such a white-emitting conversion LED. As a result ofthe small full width at half maximum of the phosphors according to thepresent disclosure (Na_(r)K_(1−r))₁(TA)₃(TD)₁(XB)₄:E where 0.2<r≤0.4,

(Rb_(r′)Li_(1−r′))₁(TA)₃(TD)₁(XB)₄:E where 0≤r′≤1,(K_(1−r″−r′″)Na_(r″)Li_(r′″))₁(TA)₃(TD)₁(XB)₄:E where 0<r″<0.5 where0<r′″<0.5, (K,Na,Li,Cs) (TA)₃(TD)₁(XB)₄:E and(Rb_(r*)Na_(1−r*))₁(TA)₃(TD)₁(XB)₄:E where 0.4≤r*<1.0 for example(Rb_(0.5)Li_(0.5)) Li₃SiO₄:Eu, (Na_(0.25)K_(0.75)) Li₃SiO₄:Eu,(Na_(0.25)K_(0.50)Li_(0.25)) Li₃SiO₄:Eu,(Cs_(0.25)Na_(0.25)K_(0.25)Li_(0.25)) Li₃SiO₄:Eu and (Rb_(0.5)Na_(0.5))Li₃SiO₄:Eu, the emission peaks exhibit a very large overlap with thetransmission range of a standard green filter, such that only littlelight is lost and the achievable color space is large.

In accordance with at least one embodiment, the phosphor has thefollowing general molecular formula:Na_(1−y*)Ca_(y*)Li_(3−2y*)Al_(3y*)Si_(1−y*)O_(4−4y*)N_(4y*):E,wherein 0<y*<0.875; advantageously 0<y*≤0.5, particularly advantageously0<y*≤0.3, very particularly advantageously 0<y*≤0.1. By way of example,y*=0.01; 0.02; 0.03, 0.04 or 0.05. E is selected from a group whichcomprises Eu, Mn, Ce, Yb and combinations thereof. Advantageously, E=Euor Eu²⁺.

Surprisingly, it has been found that the phosphor of the formulaNaLi₃SiO₄:Eu has an isotypic crystal structure with respect to the knownphosphor CaLiAl₃N₄:Eu. The fact that two compounds crystallize in anisotypic crystal structure means, in particular, that the atoms of onecompound occupy the same place within the crystal structure as thecorresponding atoms of the other compound. As a result, the linkages ofstructural units within the structures are maintained unchanged. Anisotypic crystal structure in the case of oxides and nitrides isatypical since nitrides, in comparison with oxides, usually have ahigher degree of condensation of the polyhedra, in particular thetetrahedra, within the crystal structure. This is surprisingparticularly in the present case since the degree of condensation of thephosphor according to the present disclosure of the formula NaLi₃SiO₄:Euis one, whereas typical oxosilicates have a degree of condensation ofless than or equal to 0.5. Surprisingly, the inventors have discoveredthat, proceeding from the phosphor of the molecular formulaNaLi₃SiO₄:Eu, the elements Na, Li, Si, O can be partly replaced by theelements Ca, Li, Al and N, thus resulting in a phosphor of the formulaNa_(1−y*)Ca_(y*)Li_(3−2y*)Al_(3y*)Si_(1−y)O_(4−4y*)N_(4y*):Eu. Thisphosphor is present in a mixed phase, in particular, such that withinthe crystal structure of NaLi₃SiO₄:Eu, the lattice sites are partlyoccupied by the elements Ca, Li, Al and N.

The known phosphor CaLiAl₃N₄:Eu is a phosphor which emits in the redrange of the electromagnetic spectrum, has a peak wavelength atapproximately 670 nm, has a full width at half maximum of approximately60 nm and crystallizes in an isotypic crystal structure with respect toNaLi₃SiO₄. In comparison therewith, NaLi₃SiO₄:Eu emits in the bluespectral range of the electromagnetic spectrum with a peak wavelength ofapproximately 470 nm and exhibits a more narrowband emission, that is tosay an emission having a smaller full width at half maximum than 60 nm.The mixed phase according to the present disclosure of these phosphorsadvantageously makes it possible to provide a phosphor of the formulaNa_(1−y*)Ca_(y*)Li_(3−2y*)Al_(3y*)Si_(1−y)O_(4−4y*)N_(4y*):Eu in whichthe proportion of CaLiAl₃N₄ can be varied, which is expressed by theindex y* in the formula. As a result of this variation, it is possibleto provide a phosphor which, as a result of the variable composition,allows the peak wavelength to be set in a range of between 470 nm and670 nm. The phosphor can thus be set in a targeted manner with regard tothe desired color locus, depending on requirements or application.Consequently, with just one phosphor it is possible, surprisingly, togenerate almost all colors of the visible range, from blue to red.

The peak wavelength of the phosphorNa_(1−y*)Ca_(y*)Li_(3−2y*)Al_(3y*)Si_(1−y*)O_(4−4y*)N_(4y*):E where0<y*<0.875, advantageously 0<y*≤0.5, particularly advantageously0<y*≤0.3, very particularly advantageously 0<y*≤0.1, is advantageouslyin the blue or green spectral range. The phosphor is suitable inparticular in combination with a green and red phosphor for whiteconversion LEDs, in particular for general lighting. Moreover, thephosphor is suitable for colored conversion LEDs.

In accordance with at least one embodiment, the phosphorNa_(1−y*)Ca_(y*)Li_(3−2y*)Al_(3y*)Si_(1−y*)O_(4−4y*)N_(4y*):Ecrystallizes in a tetragonal crystal system. Advantageously, thephosphor in accordance with this embodiment crystallizes in the spacegroup I4₁/a. Particularly advantageously, the phosphor in accordancewith this embodiment crystallizes in a tetragonal crystal system withthe space group I4₁/a.

In accordance with at least one embodiment, the phosphor has thefollowing general molecular formula:Na_(1−y***)Sr_(y**)Li_(3−2y***)Al_(3y***)Si_(1−y***)O_(4−4y***)N_(4y***):E,wherein 0<y***<0.875; advantageously 0<y***≤0.5, particularlyadvantageously 0<y***≤0.3. By way of example, it holds true thaty***=0.01; 0.02; 0.03, 0.04 or 0.05. E is selected from a group whichcomprises Eu, Mn, Ce, Yb and combinations thereof. Advantageously, E=Euor Eu^(2+.)

In accordance with at least one embodiment, the phosphor has the formula(MB)_(b)(TA)_(e)(TC)_(g)(TD)_(h)(XB)_(l)(XC)_(m):E,

wherein

-   -   MB is selected from a group of divalent metals which comprises        Mg, Ca, Sr, Ba, Zn, Mn, Eu, Yb, Ni, Fe, Co and combinations        thereof,    -   TA is selected from a group of monovalent metals which comprises        Li, Na, Cu, Ag and combinations thereof,    -   TC is selected from a group of trivalent metals which comprises        B, Al, Ga, In, Y, Fe, Cr, Sc, rare earths and combinations        thereof,    -   TD is selected from a group of tetravalent metals which        comprises Si, Ge, Sn, Mn, Ti, Zr, Hf, Ce and combinations        thereof,    -   XB=O and/or S    -   XC=N    -   b=1;    -   e+g+h=4;    -   l+m=4;    -   2b+e+3g+4h−2l−3m=0 and m<3.5 or l>0.5.    -   E=Eu, Ce, Yb and/or Mn, advantageously E=Eu.

In accordance with at least one embodiment, the phosphor has the formula(MB)_(b)(TA)_(e)(TC)_(g)(TD)_(h)(XB)_(l)(XC)_(m):E,

wherein

-   -   MB is selected from a group of divalent metals which comprises        Mg, Ca, Sr, Ba and combinations thereof,    -   TA is selected from a group of monovalent metals which comprises        Li, Na and combinations thereof,    -   TC is selected from a group of trivalent metals which comprises        B, Al, Ga and combinations thereof,    -   TD is selected from a group of tetravalent metals which        comprises Si, Ge and combinations thereof,    -   XC=N    -   XB=O    -   b=1;    -   e+g+h=4;    -   l+m=4;    -   2b+e+3g+4h−2l−3m=0 and m<3.5 or l>0.5.    -   E=Eu, Ce, Yb and/or Mn, advantageously E=Eu.

In accordance with at least one embodiment, the phosphor has thefollowing general molecular formula:(MB)(Si_(0.25)Al_(−1/8+r**/2)Li_(7/8−r**/2))₄(O_(1−r**)N_(r**))₄:E,wherein 0.25≤r**≤1, advantageously 0.25<r**<0.875, particularlyadvantageously 0.4≤r**≤0.8. MB is selected from a group of divalentmetals which comprises Mg, Ca, Sr, Ba and combinations thereof, andE=Eu, Ce, Yb and/or Mn, advantageously E=Eu.

In accordance with at least one embodiment, the phosphor has thefollowing general molecular formula:Sr(Si_(0.25)Al_(−1/8+r**/2)Li_(7/8−r**/2))₄(O_(1−r**)N_(r**))₄:E,wherein 0.25≤r**≤1, advantageously 0.25<r**<0.875, particularlyadvantageously 0.4≤r**≤0.8 and E=Eu, Ce, Yb and/or Mn. The phosphor is,in particular, a mixed phase of the compounds SrSiLi₃O₃N:Eu (r**=0.25)and Sr₂Si₂Al₃Li₃N₈:Eu (r**=1).

The mixed phase according to the present disclosure advantageously makesit possible to provide a phosphor in which the proportion of nitrogencan be varied, which is expressed in the formula by the index r**. As aresult of this variation, it is possible to provide a phosphor which, asa result of the variable composition, allows the peak wavelength to beset from the yellow to red spectral range. Consequently, the phosphorcan be set in a targeted manner with regard to the desired color locusand/or color rendering index, depending on requirements or application.With just one phosphor, surprisingly, it is thus possible to generatemany colors of the visible range, in particular from yellow to red.

In accordance with at least one embodiment, the phosphor(MB)(Si_(0.25)Al_(−1/8+r**/2)Li_(7/8−r**/2))₄(O_(1−r**)N_(r**))₄:E orSr(Si_(0.25)Al_(−1/8+r**/2)Li_(7/8−r**/2))₄(O_(1−r**)N_(r**))₄:Ecrystallizes in a tetragonal crystal system. Advantageously, thephosphor in accordance with this embodiment crystallizes in the spacegroup I4/m. Particularly advantageously, the phosphor in accordance withthis embodiment crystallizes in a tetragonal crystal system with thespace group I4/m.

In accordance with at least one embodiment, the phosphor has thefollowing general molecular formula:Na_(1−y**)Eu_(y**)Li_(3−2y**)Al_(3y**)Si_(1−y**)O_(4−4y**)N_(4y**):E,wherein 0<y**≤1.0, advantageously 0<y**<0.875 or 0<y**<0.5, particularlyadvantageously 0.05≤y**≤0.45, very particularly advantageously0.1≤y**≤0.4, 0.15≤y**≤0.35 or 0.2≤y**≤0.3. E=Eu, Ce, Yb and/or Mn,advantageously E=Eu.

Surprisingly, it has been found that the phosphor of the formulaNa_(1−y*)-Eu_(y**)Li_(3−2y**)Al_(3y**)Si_(1−y**)O_(4−4y**)N_(4y**):E,advantageouslyNa_(1−y**)Eu_(y**)Li_(3−2y**)Al_(3y**)Si_(1−y**)O_(4−4y**)N_(4y**):Eu,can be produced as a mixed phase between NaLi₃SiO₄:E or NaLi₃SiO₄:Eu(y**=0) and the compound EuLiAl₃N₄ (y**=1) and moreover constitutes anefficient phosphor having unique properties. This phosphor is present inparticular in a mixed phase, such that within the crystal structure ofNaLi₃SiO₄:Eu the lattice sites are partly occupied by the elements Eu,Li, Al and N.

NaLi₃SiO₄:Eu emits in the blue spectral range. The mixed phase accordingto the present disclosure of NaLi₃SiO₄:Eu and the compound EuLiAl₃N₄advantageously makes it possible to provide a phosphor of the formulaNa_(1−y*)Eu_(y**)Li_(3−2y**)Al_(3y**)Si_(1−y**)O_(4−4y**)N_(4y**):Eu inwhich the proportion of EuLiAl₃N₄ can be varied, which is expressed inthe formula by the index y**. As a result of this variation, it ispossible to provide a phosphor which, as a result of the variablecomposition, allows the peak wavelength to be set in a range from theyellow to red range. Consequently, the phosphor can be set in a targetedmanner with regard to the desired color locus, depending on requirementsor application. With just one phosphor, surprisingly, it is thuspossible to generate almost all colors of the visible range, from yellowto red.

In accordance with at least one embodiment, the phosphorNa_(1−y**)Eu_(y**)Li_(3−2y**)Al_(3y**)Si_(1−y**)O_(4−4y**)N_(4y**):Eucrystallizes in a tetragonal crystal system. Advantageously, thephosphor in accordance with this embodiment crystallizes in the spacegroup I4/m.

Particularly advantageously, the phosphor in accordance with thisembodiment crystallizes in a tetragonal crystal system with the spacegroup I4/m.

In accordance with at least one embodiment, the phosphor has the formula(MB)_(b)(TA)_(e)(TC)_(g)(XB)_(l)(XC)_(m):E,

wherein

-   -   MB is selected from a group of divalent metals which comprises        Mg, Ca, Sr, Ba, Zn, Mn, Eu, Yb, Ni, Fe, Co and combinations        thereof,    -   TA is selected from a group of monovalent metals which comprises        Li, Na, Cu, Ag and combinations thereof,    -   TC is selected from a group of trivalent metals which comprises        B, Al, Ga, In, Y, Fe, Cr, Sc, rare earth metals and combinations        thereof,    -   XB=O,    -   XC=N,    -   b=1;    -   e+g=4;    -   l+m=4;    -   2b+e+3g−2l−3m=0 and m<3.5 or l>0.5.    -   E=Eu, Ce, Yb and/or Mn, advantageously E=Eu.

In accordance with at least one embodiment, the phosphor has the formula(MB)_(b)(TA)_(e)(TC)_(g)(XB)_(l)(XC)_(m):E,

wherein

-   -   MB is selected from a group of divalent metals which comprises        Mg, Ca, Sr, Ba, Zn and combinations thereof,    -   TA is selected from a group of monovalent metals which comprises        Li, Na, Cu, Ag and combinations thereof,    -   TC is selected from a group of trivalent metals which comprises        B, Al, Ga and combinations thereof,    -   XB=O,    -   XC=N,    -   b=1;    -   e+g=4;    -   l+m=4;    -   2b+e+3g−2l−3m=0 and m<3.5 or l>0.5.    -   E=Eu, Ce, Yb and/or Mn, advantageously E=Eu.

In accordance with at least one embodiment, the phosphor has thefollowing general molecular formula:(MB)Li_(3−2x**)Al_(1+2x**)O_(4−4x**)N_(4x**):Euwhere 0<x**≤1.0, advantageously 0<x**<0.875, particularly advantageously0.125≤x**<0.875 or 0.125≤x**≤0.5, very particularly advantageously0.125≤x**≤0.45. MB is selected from a group of divalent metals whichcomprises Mg, Ca, Sr, Ba, Zn and combinations thereof.

In accordance with at least one embodiment, the phosphor has thefollowing general molecular formula:SrLi_(3−2x**)Al_(1+2x**)O_(4−4x**)N_(4x**):Euwhere 0<x**≤1.0, advantageously 0<x**<0.875, particularly advantageously0.125≤x**<0.875 or 0.125≤x**≤0.5, very particularly advantageously0.125≤x**≤0.45.

Surprisingly, it has been found that the phosphor of the formulaSrLi_(3−2x**)Al_(1+2x**)O_(4−4x**)N_(4x**):Eu can be produced as a mixedphase between SrLi₃AlO₄:Eu (x**=0) and the compound SrLiAl₃N₄ (x**=1)and moreover constitutes an efficient phosphor having unique properties.In particular, the phosphors have a small full width at half maximum.

SrLiAl₃N₄:Eu is a known phosphor exhibiting narrowband emission in thered spectral range. The mixed phase according to the present disclosureof SrLi₃AlO₄:Eu and the compound SrLiAl₃N₄ advantageously makes itpossible to provide a phosphor of the formulaSrLi_(3−2x**)Al_(1+2x**)O_(4−4x**)N_(4x**):Eu in which the proportion ofSrLiAl₃N₄ can be varied, which is expressed in the formula by the indexx**. As a result of this variation, it is possible to provide a phosphorwhich, as a result of the variable composition, allows the peakwavelength to be set in a range from the green to yellow oryellow-orange range. As a result, it is possible to achieve color lociwhich cannot be achieved with known phosphors. Consequently, thephosphor can be set in a targeted manner with regard to the desiredcolor locus in the green to yellow range, depending on requirements orapplication.

Surprisingly, it has been found that the phosphor of the formulaSrLi_(3−2x**)Al_(1+2x**)O_(4−4x**)N_(4x**):Eu, as x**increases, startingfrom x**≥0.1250, crystallizes in the same crystal structure but in theprocess the cell volume of the unit cell increases and at the same time,as x**increases, the peak wavelength is shifted into thelonger-wavelength range, in particular from the green right into the redspectral range. Thus, the phosphorSrLi_(3−2x**)Al_(1+2x**)O_(4−4x**)N_(4x**):Eu where 0.125≤x**≤1,advantageously 0.125≤x**<0.875, particularly advantageously0.125≤x**≤0.5, very particularly advantageously 0.125≤x**≤0.45, isusable in diverse ways and is suitable in particular for coloredconversion LEDs comprising SrLi_(3−2x**)Al_(1+2x**)O_(4−4x**)N_(4x**):Euas sole phosphor. In addition, the phosphors advantageously have smallvalues of full width at half maximum of less than 80 nm.

The phosphor SrLi_(3−2x**)Al_(1+2x**)O_(4−4x**)N_(4x**):Eu, inparticular where x**≥0.1250, is suitable for example for use in lightingdevices such as conversion LEDs which emit white radiation, wherein asuperimposition of the blue primary radiation and the secondaryradiation yields a white overall radiation. The phosphor is very robustand efficient and it is advantageously possible to provide a conversionLED which emits an overall radiation having a color temperature of lessthan 3600 K, in particular 3400 K±100 K, and a color locus near thePlanckian locus.

In accordance with at least one embodiment, the phosphor has thefollowing general molecular formula:SrLi_(3−2x**)Al_(1+2x**)O_(4−4x**)N_(4x**):Euwhere 0<x**<0.125, advantageously 0<x**<0.120.

The phosphor SrLi_(3−2x**)Al_(1+2x**)O_(4−4x**)N_(4x**):Eu where0<x**<0.125 surprisingly does not crystallize in an isotypic crystalstructure with respect to the crystal structure ofSrLi_(3−2x**)Al_(1+2x**)O_(4−4x**)N_(4x**):Eu where x**≥0.125. Inparticular, the phosphor where 0<x**<0.125 can form a crystal structurewhich can be described as a crystallographic superstructure of thecrystal structure of variants of the phosphor where x**≥0.125.

Advantageously, the peak wavelength of this phosphor is in the greenrange of the electromagnetic spectrum. The full width at half maximum isadvantageously smaller in comparison withSrLi_(3−2x**)Al_(1+2x**)O_(4−4x**)N_(4x**):Eu where x**≥0.125.

In accordance with at least one embodiment, the phosphor (MB)Li_(3−2x**)Al_(1+2x**)O_(4−4x**)N_(4x**):Eu orSrLi_(3−2x**)Al_(1+2x**)O_(4−4x**)N_(4x**):Eu crystallizes in atetragonal crystal system. Advantageously, the phosphor in accordancewith this embodiment crystallizes in the space group I4/m. Particularlyadvantageously, the phosphor in accordance with this embodimentcrystallizes in a tetragonal crystal system in the space group I4/m.

In accordance with at least one embodiment, the phosphor crystallizes ina crystal structure having the same atomic sequence as in UCr₄C₄,CsKNa₂Li₁₂Si₄O₁₆ or RbLi₅{Li[SiO₄]}₂. The fact that the phosphorcrystallizes in a crystal structure having the same atomic sequence asin UCr₄C₄, CsKNa₂Li₁₂Si₄O₁₆ or RbLi₅{Li[SiO₄]}₂ means, here andhereinafter, that the succession of the atoms of the phosphor followsthe same pattern as the succession of the atoms in UCr₄C₄,CsKNa₂Li₁₂Si₄O₁₆ or RbLi₅{Li[SiO₄]}₂. In other words, the crystalstructure exhibits the same structural motifs as UCr₄C₄,CsKNa₂Li₁₂Si₄O₁₆ or RbLi₅{Li[SiO₄]}₂. By way of example, the phosphor ofthe formula (Na_(0.5)K_(0.5)) Li₃SiO₃:Eu crystallizes in a crystalstructure having the same atomic sequence as in CsKNa₂Li₁₂Si₄O₁₆; inthis case, K occupies the sites of Cs and of K, Na occupies the sites ofNa, Li occupies the sites of Li, Si occupies the sites of Si, and Ooccupies the sites of O. As a result of the variation of the ionic radiiin the course of substitution with other atomic species, the absoluteposition (atomic coordinates) of the atoms may change.

The phosphor can also crystallize in a crystal structure having the sameatomic sequence as in the structures NaLi₃SiO₄ or KLi₃GeO₄ derived fromUCr₄C₄.

In accordance with at least one embodiment, the phosphor crystallizes inthe same structure type as

-   -   NaLi₃SiO₄    -   KLi₃SiO₄    -   RbLi₅{Li[SiO₄]}2    -   UCr₄C₄    -   CsKNa₂Li₁₂Si₄O₁₆ or    -   CsKNaLi₉{Li[SiO₄]}₄.

The crystal structures of the embodiments are distinguished inparticular by a three-dimensionally linked spatial network. In thiscase, TA, TB, TC, TD, TE and/or TF are surrounded by XA, XB, XC and/orXD and the resultant structural units, advantageously tetrahedra, arelinked via common corners and edges. This arrangement results in athree-dimensionally extending anionic structural unit. MA, MB, MC and/orMD are arranged in the resultant cavities and/or channels.

In accordance with at least one embodiment, the phosphor has a crystalstructure in which TA, TB, TC, TD, TE and/or TF are surrounded by XA,XB, XC and/or XD and the resultant structural units are linked viacommon corners and edges to form a three-dimensional spatial networkhaving cavities and/or channels and MA, MB, MC and/or MD are arranged inthe cavities and/or channels. In particular, the structural units aretetrahedra, wherein advantageously XA, XB, XC and/or XD occupy thecorners of the tetrahedra and TA, TB, TC, TD, TE and/or TF are arrangedin the center of the tetrahedra.

By way of example, in the crystal structure of the embodimentKLi₃SiO₄:E, which is isotypic with respect to KLi₃GeO₄, Li and Si aresurrounded by O and form the anionic structural unit in the form of aspatial network of distorted (Li/Si)O₄ tetrahedra. In the resultantcavities, the K atoms are surrounded by 8 O atoms in a distorted cubicfashion.

In the crystal structure of the exemplary embodiment RbLi₅{Li[SiO₄]}₂:E,one portion of the Li atoms and Si are surrounded by O and form theanionic structural unit in the form of a spatial network. In this case,the Si atoms are surrounded by 4 O atoms in a distorted tetrahedralfashion. The Li atoms which participate in the structural unit aresurrounded by 3 O atoms in a distorted trigonal planar fashion in theirfirst coordination sphere. With addition of further O atoms in thevicinity, the coordination can also be described as distortedtetrahedral or distorted trigonal bipyramidal. In the resultantcavities, the Rb atoms are surrounded by 8 O atoms in a distorted cubicfashion, while the other portion of the Li atoms is surrounded by 4 Oatoms in a distorted square planar fashion.

Depending on the chemical composition of the phosphors disclosed here, asevere distortion of the coordination sphere around MA, MB, MC and/or MDmay occur. In the case of the exemplary embodiment NaLi₃SiO₄:E, forexample, that has the effect that the vicinity of the Na atoms ispresent as a distorted trigonal prism or, with addition of a further Oatom, as a distorted capped cube.

The specified embodiments of the phosphor can be produced in accordancewith methods specified below. All features described for the phosphorthus also apply to the method for producing said phosphor, andvice-versa.

A method for producing a phosphor is specified.

In accordance with at least one embodiment, the phosphor has the generalmolecular formula:(MA)_(a)(MB)_(b)(MC)_(c)(MD)_(d)(TA)_(e)(TB)_(f)(TC)_(g)(TD)_(h)(TE)_(i)(TF)_(j)(XA)_(k)(XB)_(l)(XC)_(m)(XD)_(n):EIn this case, MA is selected from a group of monovalent metals, MB isselected from a group of divalent metals, MC is selected from a group oftrivalent metals, MD is selected from a group of tetravalent metals, TAis selected from a group of monovalent metals, TB is selected from agroup of divalent metals, TC is selected from a group of trivalentmetals, TD is selected from a group of tetravalent metals, TE isselected from a group of pentavalent elements, TF is selected from agroup of hexavalent elements, XA is selected from a group of elementswhich comprises halogens, XB is selected from a group of elements whichcomprises O, S and combinations thereof, XC=N and XD=C. The followingfurthermore hold true:

-   -   a+b+c+d=t;    -   e+f+g+h+i+j=u    -   k+l+m+n=v    -   a+2b+3c+4d+e+2f+3g+4h+5i+6j−k−2l−3m−4n=w    -   0.8≤t≤1    -   3.5≤u≤4    -   3.5≤v≤4    -   (−0.2)≤w≤0.2 and E=Eu, Ce, Yb and/or Mn. It advantageously holds        true that: 0≤m<0.875 v and/or v≥l>0.125 v.

The method comprises the following method steps:

A) mixing starting materials with the phosphor,

B) heating the mixture obtained under A) to a temperature T1 of between500 and 1400° C., advantageously between 700 and 1400° C.,

C) annealing the mixture at a temperature T1 of 500 to 1400° C.,advantageously between 700 and 1400° C., for 0.5 minute to 10 hours.

In one embodiment, the starting materials are present as powder.

In one embodiment, method step C) is followed by a further method step:

D) cooling the mixture to room temperature. Room temperature isunderstood to mean 20° C., in particular.

In one embodiment, method step D) is followed by method steps B) and C)again, wherein the phosphor obtained in method step D) is then heatedand annealed, respectively. The optical properties of the phosphor canbe improved by this further annealing process.

In accordance with at least one embodiment, the starting materials meltduring the process of heating the mixture obtained under A) in methodstep B).

The heating and cooling rates can be for example 250° C. per hour.

In one embodiment, method steps B), C) and/or D) take place underforming gas atmosphere. Advantageously, in the forming gas the ratio ofnitrogen:hydrogen is 92.5:7.5.

In one embodiment, method steps B), C) and/or D) take place in a tubefurnace.

In accordance with at least one embodiment, the method comprises thefollowing method step A):

A) mixing the starting materials comprising K₂CO₃, Cs₂CO₃, Na₂CO₃ and/orRb₂CO₃.

In accordance with at least one embodiment, the method comprises thefollowing method step A):

A) mixing the starting materials comprising or consisting of SiO₂,Eu₂O₃, Li₂CO₃ and at least one carbonate from K₂CO₃, Cs₂CO₃, Na₂CO₃ andRb₂CO₃. In particular, with the use of these starting materials it ispossible to produce the phosphors (Na_(r)K_(1−r)) Li₃SiO₄:Eu,(Rb_(r′)Li_(1−r′)) Li₃SiO₄:Eu and (K_(1−r″-r′″)Na_(r″)Li_(r′″))Li₃SiO₄:Eu, advantageously NaLi₃SiO₄:Eu, KLi₃SiO₄:Eu, (Na_(0.5)K_(0.5))Li₃SiO₄:Eu, (Rb_(0.5)Li_(0.5)) Li₃SiO₄:Eu, (Na_(0.25)K_(0.75))Li₃SiO₄:Eu and (Na_(0.25)K_(0.5)Li_(0.25)) Li₃SiO₄:Eu.

In accordance with at least one embodiment, the method comprises thefollowing method step A):

A) mixing the starting materials comprising or consisting of CaO, NaF,LiN₃, Li₂O, LiAlH₄, AlF₃, SiO₂ and EuF₃. In particular, with the use ofthese starting materials it is possible to produce a phosphor of theformula Na_(1−y*)Ca_(y*)Li_(3−2y*)Al_(3y*)Si_(1−y)O_(4−4y*)N_(4y*):Eu,for exampleNa_(0.97)Ca_(0.03)Li_(2.94)Al_(0.09)Si_(0.97)O_(3.88)N_(0.12):Eu.

The production method can be carried out very simply in comparison withmany other methods for producing phosphors. In particular, no protectivegas atmosphere is required since the products are insensitive tomoisture or oxygen. Moreover, the synthesis is carried out at moderatetemperatures and is therefore very energy-efficient. The requirementsmade, for example, of the furnace used are thus low. The startingmaterials are commercially available in a cost-effective manner and arenon-toxic.

In accordance with at least one embodiment, the lighting device, inparticular the conversion LED, emits a white radiation during operation.The radiation can be composed of a superimposition of the primaryradiation and the secondary radiation or only of the secondaryradiation.

In accordance with at least one embodiment, the phosphor emits asecondary radiation having a peak wavelength in the blue or blue-greenspectral range of the electromagnetic spectrum. In order to generate awhite overall radiation, the conversion element can comprise a secondand a third phosphor. In particular, the second phosphor can beconfigured partly to convert the electromagnetic primary radiation intoan electromagnetic secondary radiation that is in the red spectral rangeof the electromagnetic spectrum during operation of the lighting device.The third phosphor can be configured in particular partly to convert theelectromagnetic primary radiation into an electromagnetic secondaryradiation that is in the green spectral range of the electromagneticspectrum during operation of the lighting device. A superimposition ofthe blue, green and red secondary radiation produces a white luminousimpression. The lighting device, in particular the conversion LED, inaccordance with this embodiment is suitable in particular for generallighting.

The conversion of the UV or blue primary radiation into a secondaryradiation having a somewhat longer wavelength in the blue or blue-greenrange of the electromagnetic spectrum increases the efficiency of thelighting device, in particular of the conversion LED. In comparison withthe primary radiation, the peak wavelength of the secondary radiation iscloser to the maximum of eye sensitivity at 555 nm, as a result of whichthe emitted radiation has a higher overlap with the eye sensitivitycurve and is thus perceived as brighter.

In accordance with at least one embodiment, the phosphor emits asecondary radiation having a peak wavelength in the green spectral rangeof the electromagnetic spectrum. In order to generate a white overallradiation, the conversion element can comprise a second phosphor, whichcan be configured partly to convert the electromagnetic primaryradiation into an electromagnetic secondary radiation in the redspectral range of the electromagnetic spectrum during operation of thelighting device. A superimposition of the blue primary radiation and thegreen and red secondary radiation produces a white luminous impression.The lighting device, in particular the conversion LED, in accordancewith this embodiment is suitable in particular for backlightingapplications.

The third phosphor having a peak wavelength in the green spectral rangecan be selected from a group comprising R-SiAlONs, α-SiAlONs,chlorosilicates, orthosilicates, siliconoxynitrides (SiONs), garnets andcombinations thereof.

In accordance with one embodiment, the garnet phosphor can be selectedfrom the material system (Y, Lu, Gd)₃(Al,Ga)₅O₁₂:Ce or(Y,Lu,Gd)₃(Al)₅O₁₂:Ce. Advantageously, the garnet phosphor is selectedfrom the material system (Y,Lu)₃Al₅O₁₂:Ce and (Y,Lu)₃(Al,Ga)₅O₁₂:Ce. Byway of example, the phosphor is Y₃Al₅O₁₂:Ce.

The α-SiAlONs can have for example the following molecular formula:M_(t)Si_(12−(t′+t″))Al_((t′+t″))O_(n)N_(16−n):Eu where M=Ca, Mg, Y,advantageously Ca.

The chlorosilicates can have for example the following molecularformula: (Ca,Sr,Ba,Eu)₈Mg(SiO₄)₄Cl₂.

The siliconoxynitrides can have for example the following molecularformula:(EA*_(1-t′″)Eu_(t′″))Si₂O₂N₂where 0<t′″≤0.2, advantageously 0<t′″≤0.15, particularly advantageously0.02≤t′″≤0.15 and EA*=Sr, Ca, Ba and/or Mg. Preference is given to(Sr_(1t′″−o)EA*_(o)Eu_(t′″))Si₂O₂N₂ where EA*=Ba, Ca and/or Mg and0≤o<0.5.

The second phosphor having a peak wavelength in the red spectral rangecan be for example a nitridosilicate or a nitridoaluminate. Inparticular, the nitridosilicate can be selected from the materialsystems (Ca,Sr,Ba,Eu)₂(Si,Al)₅(N,O)₈, (Ca,Sr,Ba,Eu)AlSi(N,O)₃,(Ca,Sr,Ba,Eu)AlSi(N,O)₃.Si₂N₂O, (Ca,Sr,Ba,Eu)₂Si₅N₈, (Ca,Sr,Ba,Eu)AlSiN₃and combinations thereof. The nitridoaluminate can have the formulaMLiAl₃N₄:Eu (M=Ca,Sr).

Furthermore, the second phosphor can be selected from a material systemhaving a peak wavelength in the red spectral range, which is describedin the patent application WO2015/052238A1, the disclosure content ofwhich in this regard is hereby incorporated by reference in itsentirety. By way of example, the second phosphor has the formulaSr(Sr,Ca)Si₂Al₂N₆:Eu.

The second phosphor having a peak wavelength in the red spectral rangecan also be a phosphor having the molecular formula A₂[SiF₆]:Mn⁴⁺ whereA=Li, Na, K, Rb, Cs, for example K₂SiF₆:Mn⁴⁺.

The second phosphor having a peak wavelength in the red spectral rangecan also be Mg₄GeO_(5.5)F:Mn.

In accordance with at least one embodiment, the lighting device, inparticular the conversion LED, is configured to emit a white radiation.In this case, the phosphor has the formula(Na_(r)K_(1-r))₁(TA)₃(TD)₁(XB)₄:E where 0≤r≤0.05, advantageously r=0.Advantageously, TA=Li, TD=Si, XB=O and E=Eu, Ce, Yb and/or Mn,advantageously E=Eu. By way of example, the phosphor is KLi₃SiO₄:Eu. Thephosphor exhibits very broadband emission from the blue to red spectralrange, thus giving rise to a white-colored luminous impression. In thiscase, it is advantageously possible for the conversion element toconsist of this phosphor or this phosphor and the matrix material. Inparticular, the conversion element or the lighting device, in particularthe conversion LED, in accordance with this embodiment comprises nofurther phosphor. The phosphor can thus be present, therefore, as solephosphor in the conversion element or the lighting device, in particularthe conversion LED. The lighting device, in particular the conversionLED, has a high efficiency and a high color rendering index. Inparticular the lighting device, in particular the conversion LED, inaccordance with this embodiment emits warm-white radiation having acolor temperature of less than 3500 K, in particular less than 3000 K.Thus, this lighting device, in particular this conversion LED, issuitable in particular for general lighting.

In comparison with known white-emitting conversion LEDs which use ablue-emitting semiconductor chip and a red and green phosphor forgenerating white light, here the complicated binning of thesemiconductor chips can be dispensed with or can be carried out at leastwith a greater tolerance. It is possible to use semiconductor chipswhich have a primary radiation that is not perceived or is only scarcelyperceived by the human eye (300 nm to 430 nm or 440 nm). Production-,temperature- or forward-current-dictated fluctuations of the primaryradiations do not adversely affect the overall radiation properties. Incomparison with the use of two or more phosphors, color adaptation byvarying the concentrations of the phosphors is not necessary since theemission spectrum is generated by only one phosphor and is thusconstant. The conversion LEDs can thus be produced with a highthroughput since color adaptation or complicated chip binning is notnecessary. No color shifts or other adverse effects on the emissionspectrum as a result of selective degradation of only one phosphoroccur. A partial conversion of the primary radiation can also be carriedout depending on the application. Since it is possible to excite thephosphor with a primary radiation in the range of 300 nm to 430 nm or440 nm, a contribution of the primary radiation, advantageously in theshort-wave blue range of the electromagnetic spectrum, to the overallradiation has the effect that objects illuminated thereby appear whiter,more radiant and therefore more attractive. By way of example, opticalbrightening agents in textiles can thereby be excited.

In accordance with at least one embodiment, the lighting device, inparticular the conversion LED, is configured to emit a white radiation.In this case, the phosphor has the formula(Na_(r)K_(1−r))₁(TA)₃(TD)₁(XB)₄:E or (Na_(r)K_(1-r)) Li₃SiO₄:E where0.05<r≤0.2, advantageously 0.1<r≤0.2 where E=Eu, Ce, Yb and/or Mn,advantageously E=Eu. By way of example, the phosphor isNa_(0.125)K_(0.875)Li₃SiO₄:Eu. The phosphor exhibits broadband emissionfrom the green to red spectral range, thus resulting in a white overallradiation through the superimposition of a blue primary radiation andthe secondary radiation. In this case, it is advantageously possible forthe conversion element to consist of this phosphor or this phosphor andthe matrix material. In particular, the conversion element or thelighting device, in particular the conversion LED, in accordance withthis embodiment comprises no further phosphor. The phosphor can thus bepresent, therefore, as sole phosphor in the conversion element or thelighting device, in particular the conversion LED. In contrast toconversion LEDs comprising a plurality of phosphors, therefore, no colorshifts or other adverse effects on the emission spectrum as a result ofselective degradation of only one phosphor occur.

The lighting device, in particular the conversion LED, has in particulara high color rendering index, even though no further red phosphor ispresent. In particular, the lighting device, in particular theconversion LED, in accordance with this embodiment emits cold-whiteradiation having a color temperature of more than 6500 K, advantageouslymore than 8000 K. The maximum value of the color temperature can be 10000 K. Therefore, this lighting device, in particular this conversionLED, is suitable in particular for general lighting, for example foroffice spaces. Studies prove that cold-white overall radiation in thecase of general lighting can increase the ability to concentrate, sincethe production of melatonin can be reduced by the high proportion ofblue in the overall radiation.

In accordance with at least one embodiment, the lighting device, inparticular the conversion light-emitting diode, is configured to emit awhite radiation, wherein the phosphor has the formula(Na_(r)K_(1−r))₁(TA)₃(TD)₁(XB)₄:E where 0.2<r≤0.4, advantageously0.2<r≤0.3, (Rb_(r′)Li_(1-r′))₁(TA)₃(TD)₁(XB)₄:E where 0≤r′≤1,advantageously 0.25≤r′≤0.75, particularly advantageously 0.4≤r′≤0.6,(K_(1r″r′″)Na_(r″)Li_(r′″))₁(TA)₃(TD)₁(XB)₄:E where 0<r″<0.5 and0<r′″<0.5, advantageously 0.1<r′<0.4 and 0.1<r′″<0.4, particularlyadvantageously 0.2<r″<0.3 and 0.2<r′″<0.3,(Cs,Na,K,Li)₁(TA)₃(TD)₁(XB)₄:E, advantageously(Cs_(0.25)Na_(0.25)K_(0.25)Li_(0.25)) (TA)₃(TD)₁(XB)₄:E or(Rb_(r*)Na_(1-r*))₁(TA)₃(TD)₁(XB)₄:E where 0.4≤r*<0.875, advantageously0.4≤r*≤0.75, particularly advantageously 0.4≤r*≤0.6, very particularlyadvantageously r*=0.5. Advantageously, TA=Li, TD=Si and XB=O.Particularly advantageously, TA=Li, TD=Si, E=Eu and XB=O. The conversionelement comprises at least one second phosphor configured partly toconvert the electromagnetic primary radiation into an electromagneticsecondary radiation that is in the red spectral range of theelectromagnetic spectrum during operation of the lighting device, inparticular the conversion LED.

In accordance with at least one embodiment, the phosphor has the formula(Na_(r)K_(1−r))₁(TA)₃(TD)₁(XB)₄:E where 0.2<r≤0.4, advantageously0.2<r≤0.3, particularly advantageously r=0.25,(Rb_(r′)Li_(1−r′))₁(TA)₃(TD)₁(XB)₄:E where 0≤r′≤1, advantageously0.25≤r′≤0.75, particularly advantageously 0.4≤r′≤0.6,(K_(1−r″−r′″)Na_(r″)Li_(r′″))₁(TA)₃(TD)₁(XB)₄:E where 0<r″<0.5 and0<r′″<0.5, advantageously 0.1<r″<0.4 and 0.1<r′″<0.4, particularlyadvantageously 0.2<r″<0.3 and 0.2<r′″<0.3,(Cs,Na,K,Li)₁(TA)₃(TD)₁(XB)₄:E, advantageously(Cs_(0.25)Na_(0.25)K_(0.25)Li_(0.25)) (TA)₃(TD)₁(XB)₄:E or(Rb_(r*)Na_(1-r′))₁(TA)₃(TD)₁(XB)₄:E where 0.4≤r*<0.875, advantageously0.4≤r*≤0.75, particularly advantageously 0.4≤r*≤0.6, very particularlyadvantageously r*=0.5. Advantageously, TA=Li, TD=Si and XB=O.Particularly advantageously, TA=Li, TD=Si, E=Eu and XB=O. The peakwavelength of the phosphor is advantageously in the green spectral rangeand has a full width at half maximum of less than 50 nm. The conversionelement comprises a second phosphor configured partly to convert theelectromagnetic primary radiation into an electromagnetic secondaryradiation that is in the red spectral range of the electromagneticspectrum during operation of the lighting device. It is possible for theconversion element to consist of the phosphor and the second phosphor orof the phosphor, the second phosphor and the matrix material. Inparticular, the conversion element or the conversion LED in accordancewith this embodiment does not comprise a further phosphor. The phosphorand the second phosphor can thus be present, therefore, as solephosphors in the conversion element or the lighting device, inparticular the conversion LED. A superimposition of the primaryradiation and the secondary radiation in the red and green spectralrange gives a white-colored luminous impression.

A particularly large bandwidth of colors can advantageously be renderedwith a lighting device, in particular with a conversion LED, inaccordance with this embodiment. Therefore, the lighting device, inparticular the conversion LED, in accordance with this embodiment issuitable in particular for backlighting applications for displayelements such as displays.

In the case of LCD displays (“liquid crystal displays”) and otherdisplays, the colors are rendered by the primary colors red, green andblue. The bandwidth of colors which can be rendered on a display istherefore limited by the spanned color triangle of the colors red, greenand blue. These colors are correspondingly filtered out from thespectrum for backlighting by red, green and blue color filters. However,the wavelength range of the transmitted radiation of the color filtersis still very wide. Therefore, light sources having very narrowbandemissions, that is to say a small full width at half maximum, in thegreen, blue and red spectral range are required in order to cover thewidest possible color space. As light sources for backlightingapplications, predominantly a blue-emitting semiconductor chip with aphosphor having a peak wavelength in the green and a phosphor having apeak wavelength in the red spectral range are combined, wherein thephosphors have the smallest possible full width at half maximum for theemission. Ideally the emission peaks are in this case congruent with thetransmission range of the respective color filter in order to lose aslittle light as possible, to achieve the maximum efficiency and toreduce crosstalk or an overlap of the different color channels, whichlimits the achievable color space.

As a result of the small full width at half maximum of the phosphorsaccording to the present disclosure (Na_(r)K_(1-r))₁(TA)₃(TD)₁(XB)₄:Ewhere 0.2<r≤0.4, (Rb_(r′)Li_(1−r′))₁(TA)₃(TD)₁(XB)₄:E where 0≤r′≤1,(K_(1−r″−r′″)Na_(r″)Li_(r′″)) (TA)₃(TD)₁(XB)₄:E where 0<r″<0.5 and0<r′″<0.5, (Cs,Na,K,Li)₁(TA)₃(TD)₁(XB)₄:E or(Rb_(r*)Na_(1-r*))₁(TA)₃(TD)₁(XB)₄:E where 0.4≤r*<0.875, for example(Rb_(0.5)Li_(0.5)) Li₃SiO₄:Eu, (Na_(0.25)K_(0.75)) Li₃SiO₄:Eu,(Na_(0.25)K_(0.50)Li_(0.25)) Li₃SiO₄:Eu,(Cs_(0.25)Na_(0.25)K_(0.25)Li_(0.25)) Li₃SiO₄:Eu or (Rb_(0.5)Na_(0.5))Li₃SiO₄:Eu, the emission peaks exhibit a very large overlap with thetransmission range of a standard green filter (having a full width athalf maximum in the range of typically 70 to 120 nm), such that onlylittle light is lost and the achievable color space is large. Inparticular, a phosphor having a small full width at half maximum, suchas K₂SiF₆:Mn, Mg₄GeO_(5.5)F:Mn, SrLiAl₃N₄:Eu or Sr(Sr, Ca) Si₂Al₂N₆:Eu,is used as second phosphor. In particular, the combination of a greenand a red phosphor having a small full width at half maximum results ina large color space being covered.

In accordance with at least one embodiment, the lighting device, inparticular the conversion LED, is configured to emit a white radiation.In this case, the phosphor has the formula(Na_(r)K_(1−r))₁(TA)₃(TD)₁(XB)₄:E or (Na_(r)K_(1-r))Li₃SiO₄:E where0.05<r≤0.2, advantageously 0.1<r≤0.2 where E=Eu, Ce, Yb and/or Mn,advantageously E=Eu. By way of example, the phosphor isNa_(0.125)K_(0.87)Li₃SiO₄:Eu. The phosphor advantageously exhibitsbroadband emission from the green to red spectral range. In conjunctionwith a blue primary radiation, the overall radiation exhibits a verylarge overlap with the transmission range of a standard green, red andblue filter, such that only little light is lost and the achievablecolor space is large. It is thus advantageously possible for theconversion element to consist of this phosphor or this phosphor and thematrix material. In particular, the conversion element or the lightingdevice, in particular the conversion LED, in accordance with thisembodiment does not have a further phosphor. The phosphor can thus bepresent, therefore, as sole phosphor in the conversion element or thelighting device, in particular the conversion LED. Therefore, thislighting device, in particular this conversion LED, is suitable inparticular for backlighting applications.

In accordance with at least one embodiment, the lighting device, inparticular the conversion light-emitting diode, is configured to emit agreen radiation; the phosphor has the formula(Na_(r)K_(1-r))₁(TA)₃(TD)₁(XB)₄:E where 0.2<r≤0.4, advantageously0.2<r≤0.3, particularly advantageously r=0.25,(Rb_(r′)Li_(1-r′))₁(TA)₃(TD)₁(XB)₄:E where 0≤r′≤1, advantageously0.25≤r′≤0.75, particularly advantageously 0.4≤r′≤0.6,(K_(1−r″−r′″)Na_(r″)Li_(r′″))₁(TA)₃(TD)₁(XB)₄:E where 0<r″<0.5 and0<r′″<0.5, advantageously 0.1<r″<0.4 and 0.1<r′″<0.4, particularlyadvantageously 0.2<r″<0.3 and 0.2<r′″<0.3,(Cs,Na,K,Li)₁(TA)₃(TD)₁(XB)₄:E, advantageously(Cs_(0.25)Na_(0.25)K_(0.25)Li_(0.25)) (TA)₃(TD)₁(XB)₄:E or(Rb_(r*)Na_(1-r*))₁(TA)₃(TD)₁(XB)₄:E 0.4≤r*<0.875, advantageously0.4≤r*≤0.75, particularly advantageously 0.4≤r*≤0.6, very particularlyadvantageously r*=0.5. Advantageously, TA=Li, TD=Si and XB=O.Particularly advantageously, TA=Li, TD=Si, E=Eu and XB=O. The peakwavelength of the phosphor is in the green spectral range, inparticular, and has a full width at half maximum of less than 50 nm. Itis possible for the conversion element to consist of this phosphor orthis phosphor and the matrix material. In particular, the conversionelement or the lighting device, in particular the conversion LED, inaccordance with this embodiment does not have a further phosphor. Thephosphor can thus be present, therefore, as sole phosphor in theconversion element or the lighting device, in particular the conversionLED.

Green light-emitting diodes, which emit a radiation in the greenwavelength range, can be obtained firstly by means of semiconductorchips which emit green directly or conversion LEDs having asemiconductor chip and a green phosphor. Semiconductor chips which emitgreen directly exhibit a very low quantum efficiency. In the case of theconversion LEDs, the primary radiation can on the one hand be convertedcompletely into green secondary radiation (full conversion) or on theother hand be converted only partly into green secondary radiation(partial conversion), and the remaining proportion of primary radiationis filtered out by means of a filter, such that the lighting deviceemits exclusively or almost exclusively secondary radiation, inparticular green secondary radiation.

(Y,Lu)₃(Al,Ga)₅O₁₂:Ce, orthosilicates or oxonitridoorthosilicates areconventionally used as green phosphors. The conventional conversion LEDsoften have a low efficiency and color purity. In order to avoid thesedisadvantages, filters are used to adapt the emission. However, thisadversely affects the total power of the conversion LED.

Lighting devices, in particular conversion LEDs, comprising the greenphosphor according to the present disclosure of the formula(Na_(r)K_(1-r))₁(TA)₃(TD)₁(XB)₄:E where 0.2<r≤0.4,(Rb_(r′)Li_(1-r′))₁(TA)₃(TD)₁(XB)₄:E where 0≤r′≤1,(K_(1-r″-r′″)Na_(r″)Li_(r′″))₁(TA)₃(TD)₁(XB)₄:E where 0<r″<0.5 and0<r′″<0.5, (Cs,Na,K,Li)₁(TA)₃(TD)₁(XB)₄:E, advantageously(Cs_(0.25)Na_(0.25)K_(0.25)Li_(0.25)) (TA)₃(TD)₁(XB)₄:E or(Rb_(r*)Na_(1-r*))₁(TA)₃(TD)₁(XB)₄:E where 0.4≤r*<0.875, for example(Rb_(0.5)Li_(0.5)) Li₃SiO₄:Eu, (Na_(0.25)K_(0.75)) Li₃SiO₄:Eu,(Na_(0.25)K_(0.50)Li_(0.25)) Li₃SiO₄:Eu,(Cs_(0.25)Na_(0.25)K_(0.25)Li_(0.25)) Li₃SiO₄:Eu or (Rb_(0.5)Na_(0.5))Li₃SiO₄:Eu, are by contrast very efficient and exhibit a high colorpurity and a high power even without the use of a color filter.

In accordance with at least one embodiment, the lighting device, inparticular the conversion light-emitting diode, is configured to emit awhite radiation. The phosphor has the formula(Na_(r)K_(1−r))₁(TA)₃(TD)₁(XB)₄:E where 0.4<r≤1, advantageously0.45<r≤1, very particularly advantageously r=0.5 or 1.

Advantageously, TA=Li, TD=Si and XB=O. Alternatively, the phosphor hasthe formula (Rb_(r*)Na_(1-r*))₁(TA)₃(TD)₁(XB)₄:E, wherein 0<r*<0.4, forexample r*=0.05; 0.1; 0.15; 0.2; 0.25; 0.3; 0.35, advantageously0.1≤r*≤0.35, particularly advantageously 0.2≤r*≤K 0.3, very particularlyadvantageously r*=0.25 or (Cs,Na,Rb,Li)₁(TA)₃(TD)₁(XB)₄:E,(Cs,Na,K)₁(TA)₃(TD)₁(XB)₄:E and (Rb,Na,K)₁(TA)₃(TD)₁(XB)₄:E.Advantageously, TA=Li, TD=Si and XB=O. By way of example, the phosphorhas the formula NaLi₃SiO₄:Eu, (Na_(0.5)K_(0.5)) Li₃SiO₄:Eu,(Rb_(0.25)Na_(0.75)) Li₃SiO₄:Eu, (Cs_(0.25)Na_(0.25)Rb_(0.25)Li_(0.25))Li₃SiO₄:Eu, (Cs_(0.25)Na_(0.5)K_(0.25)) Li₃SiO₄:Eu or(Rb_(0.25)Na_(0.5)K_(0.25)) Li₃SiO₄:Eu. The peak wavelength of thesephosphors is advantageously in the blue spectral range, in particular inthe range of between 450 nm and 500 nm. The conversion element comprisesa second and a third phosphor, wherein the second phosphor is configuredpartly to convert the electromagnetic primary radiation into anelectromagnetic secondary radiation that is in the red spectral range ofthe electromagnetic spectrum, and the third phosphor is configured toconvert the electromagnetic primary radiation into an electromagneticsecondary radiation that is in the green spectral range of theelectromagnetic spectrum during operation of the lighting device. It ispossible for the conversion element to consist of the phosphor, thesecond and third phosphors or of the phosphor, the second and thirdphosphors and the matrix material. In particular, the conversion elementor the lighting device, in particular the conversion LED, in accordancewith this embodiment does not have a further phosphor. The phosphor andthe second and third phosphors can thus be present, therefore, as solephosphors in the conversion element or the lighting device, inparticular the conversion LED. A superimposition of the secondaryradiations in the blue, red and green spectral range gives awhite-colored luminous impression. The lighting device, in particularconversion LED in accordance with this embodiment is suitable inparticular for general lighting.

Known white-emitting conversion LEDs use a semiconductor chip whichemits a blue primary radiation, and at least one red and green phosphor.A superimposition of the blue primary radiation and the red and greensecondary radiation gives rise to white light. What is disadvantageousabout this solution is that the epitaxially grown semiconductor chips,based for example on GaN or InGaN, may have fluctuations in the peakwavelength of the emitted primary radiation. This leads to fluctuationsin the white overall radiation, such as a change in the color locus andthe color rendering, since the primary radiation contributes the blueportion to the overall radiation. This is problematic particularly whena plurality of semiconductor chips are used in a device. In order toprevent fluctuations, the semiconductor chips have to be sorted inaccordance with their color loci (“binning”). The narrower thetolerances set with regard to the wavelength of the emitted primaryradiation, the higher the quality of devices which consist of more thanone semiconductor chip. However, even after sorting with narrowtolerances, the peak wavelength of the semiconductor chips can changesignificantly in the case of variable operating temperatures and forwardcurrents. In general lighting and other applications, this may lead to achange in the optical properties, such as the color locus and the colortemperature. An additional factor is that for conventional solutions inthe range of 450 nm to 500 nm of the electromagnetic spectrum there is aspectral gap in the emission spectrum in which no or only very littlelight is emitted. This results in a reduction of the color renderingindex in comparison with the reference light source.

The phosphor (Na_(r)K_(1-r))₁(TA)₃(TD)₁(XB)₄:E where 0.4<r≤1, forexample NaLi₃SiO₄:Eu, (Rb_(r*)Na_(1-r*))₁(TA)₃(TD)₁(XB)₄:E, where0<r*<0.4, (Cs,Na,Rb,Li)₁(TA)₃(TD)₁(XB)₄:E, (Cs,Na,K)₁(TA)₃(TD)₁(XB)₄:Eor (Rb,Na,K)₁(TA)₃(TD)₁(XB)₄:E or (Na_(0.5)K_(0.5))Li₃SiO₄:Eu, can beexcited efficiently with a primary radiation of 300 nm to 440 nm. Thecombination of a semiconductor chip with a primary radiation of 300 nmto 440 nm, for example based on GaInN, leads to the emission of asecondary radiation in the blue spectral range which is stable over asignificantly wider temperature range and larger ranges for the forwardcurrents. Since the primary radiation of 300 nm to 440 nm is not visibleor is scarcely visible, a wide variety of semiconductor chips can beused as primary radiation source and a constant and stable emissionspectrum of the conversion LED can nevertheless be obtained. In thisregard complex “binning” of the semiconductor chips can be avoided orsimplified and the efficiency can be increased. As a result of a peakwavelength of the phosphor in the range of 450 nm and 500 nm, theemission is increased in this range. The color rendering index can thusadvantageously be increased.

In accordance with at least one embodiment, the lighting device, inparticular the conversion light-emitting diode, is configured to emit awhite radiation. The phosphor has the formulaNa_(1−y*)Ca_(y*)Li_(3−2y*)Al_(3y*)Si_(1−y*)O_(4−4y*)N_(4y*):E where0<y*<0.875, advantageously 0<y*≤0.5, particularly advantageously0<y*≤0.3, very particularly advantageously 0<y*≤0.1, for exampleNa_(0.97)Ca_(0.03)Li_(2.94)Al_(0.09)Si_(0.97)O_(3.88)N_(0.12):Eu. Thepeak wavelength of the phosphor is advantageously in the blue or greenspectral range, in particular in the range of between 470 nm and 560 nm,advantageously between 470 nm and 520 nm. The conversion elementcomprises in particular a second and a third phosphor, wherein thesecond phosphor is configured partly to convert the electromagneticprimary radiation into an electromagnetic secondary radiation that is inthe red spectral range of the electromagnetic spectrum, and the thirdphosphor is configured to convert the electromagnetic primary radiationinto an electromagnetic secondary radiation that is in the greenspectral range of the electromagnetic spectrum during operation of thelighting device. In this case, the third phosphor has in particular anelectromagnetic secondary radiation having a peak wavelength of morethan 520 nm. It is possible for the conversion element to consist of thephosphor, the second and third phosphors or of the phosphor, the secondand third phosphors and the matrix material. In particular, theconversion element or the lighting device, in particular the conversionLED, in accordance with this embodiment does not have a furtherphosphor. The phosphor and the second and third phosphors can thus bepresent, therefore, as sole phosphors in the conversion element or thelighting device, in particular the conversion LED. A superimposition ofthe secondary radiations gives a white-colored luminous impression.Radiation in the range of 450 nm to 500 nm of the electromagneticspectrum is also emitted as a result of the use of the phosphorNa_(1−y*)Ca_(y*)Li_(3−2y*)Al_(3y*)Si_(1−y*)O_(4−4y*)N_(4y*):E. With theuse of standard phosphors, a spectral gap in the overall emissionspectrum often prevails here, in which therefore no or only very littlelight is emitted. As a result, the overall radiation almost continuouslycovers in particular the visible range of the electromagnetic spectrum,whereby the overall radiation has a high color rendering index. Thelighting device, in particular conversion LED, in accordance with thisembodiment is suitable in particular for general lighting.

In accordance with at least one embodiment, the lighting device, inparticular the conversion light-emitting diode, is configured to emit awhite radiation. The phosphor has the formulaSr(Si_(0.25)Al_(−1/8+r**/2)Li_(7/8−r**/2))₄(O_(1−r**)N_(r**))₄:E,wherein 0.25≤r**≤1, advantageously 0.25<r**<0.875, particularlyadvantageously 0.4≤r**≤0.8. Advantageously, E=Eu. The peak wavelength ofthe phosphor is advantageously in the yellow to red spectral range. Theconversion element can comprise a further phosphor, wherein awhite-colored luminous impression is produced by a superimposition ofthe secondary radiations and/or the primary radiation and the secondaryradiations. Since the peak wavelength of the phosphorSr(Si_(0.25)Al_(−1/8+r**/2)Li_(7/8−r**/2))₄ (O_(1−r**)N_(r**))₄:E can bein the yellow to red spectral range depending on the proportion of r**,the choice of the further phosphor within the conversion LED forgenerating white light depends on the peak wavelength of the phosphorSr(Si_(0.25)Al_(−1/8+r**/2)Li_(7/8−r**/2))₄ (O_(1−r**)N_(r**))₄:E.

In accordance with at least one embodiment, the lighting device, inparticular the conversion light-emitting diode, is configured to emit aradiation that is in the yellow to red spectral range. The phosphor hasthe formulaNa_(1−y*)Eu_(y**)Li_(3−2y**)Al_(3y**)Si_(1−y**)O_(4−4y**)N_(4y**):Eu,wherein 0<y**≤1.0, advantageously 0<y**<0.875 or 0<y**<0.5, particularlyadvantageously 0.05≤y**≤0.45, very particularly advantageously0.1≤y**≤0.4, 0.15≤y**≤0.35 or 0.2≤y**≤0.3. It is possible for theconversion element to consist of this phosphor or this phosphor and thematrix material. In particular, the conversion element or the lightingdevice, in particular the conversion LED, in accordance with thisembodiment does not have a further phosphor. The phosphor can thus bepresent, therefore, as sole phosphor in the conversion element or thelighting device, in particular the conversion LED.

In accordance with at least one embodiment, the lighting device, inparticular the conversion light-emitting diode, is configured to emit aradiation that is in the yellow or yellow-orange spectral range. Thephosphor has the formulaNa_(1−y**)Eu_(y**)Li_(3−2y**)Al_(3y**)Si_(1−y**)O_(4−4y**)N_(4y**):Eu,wherein 0.1≤y**≤0.4, 0.15≤y**≤0.35 or 0.2≤y**≤0.3. Conversionlight-emitting diodes of this embodiment are suitable in particular forthe use thereof in warning lights and flashing lights in motor vehicles.The inventors have been able to show that the color loci of the overallradiation of the conversion light-emitting diode of this embodiment liein the color space defined by the ECE/UNECE for flashing lights in motorvehicles in Europe and in the color space defined by the SAE forflashing lights in motor vehicles in North America.

In particular, the electromagnetic primary radiation is almostcompletely absorbed by the phosphorNa_(1−y**)Eu_(y**)Li_(3−2y**)Al_(3y**)Si_(1−y**)O_(4−4y**)N_(4y**):Euand emitted in the form of an electromagnetic secondary radiation. Theemitted radiation or overall radiation of the lighting device, inparticular of the conversion LED, in accordance with this embodimentthus almost completely corresponds to the electromagnetic secondaryradiation.

Yellow or orange-yellow light-emitting diodes, which emit a radiation inthe yellow or yellow-orange wavelength range, can firstly be obtained bymeans of semiconductor chips on the basis of InGaAlP which emit directlyin this spectral range or conversion LEDs having a semiconductor chipand a yellow phosphor. However, semiconductor chips which emit yellowdirectly exhibit a very low quantum efficiency in comparison withconversion LEDs.

In accordance with at least one embodiment, the lighting device, inparticular the conversion light-emitting diode, is configured to emit ablue radiation. The phosphor has the formula(Na_(r)K_(1-r))₁(TA)₃(TD)₁(XB)₄:E where 0.4<r≤1, advantageously0.45<r≤1, very particularly advantageously r=0.5. Advantageously, TA=Li,TD=Si and XB=O. Alternatively, the phosphor has the formula(Rb_(r*)Na_(1-r*))₁(TA)₃(TD)₁(XB)₄:E, wherein 0<r*<0.4, advantageously0.1≤r*≤0.35, particularly advantageously 0.2≤r*≤0.3, very particularlyadvantageously r*=0.25 or (Cs,Na,Rb,Li)₁(TA)₃(TD)₁(XB)₄:E,(Cs,Na,K)₁(TA)₃(TD)₁(XB)₄:E and (Rb,Na,K)₁(TA)₃(TD)₁(XB)₄:E. By way ofexample, the phosphor has the formula NaLi₃SiO₄:Eu or (Na_(0.5)K_(0.5))Li₃SiO₄:Eu, (Rb_(0.25)Na_(0.75)) Li₃SiO₄:Eu or(Cs_(0.25)Na_(0.25)Rb_(0.25)Li_(0.25)) Li₃SiO₄:Eu,(Cs_(0.25)Na_(0.5)K_(0.25)) Li₃SiO₄:Eu or (Rb_(0.25)Na_(0.5)K_(0.25))Li₃SiO₄:Eu. The peak wavelength of these phosphors is in the bluespectral range. It is possible for the conversion element to consist ofthis phosphor or this phosphor and the matrix material. In particular,the conversion element or the lighting device, in particular theconversion LED, in accordance with this embodiment does not have afurther phosphor; the phosphor can thus be present, therefore, as solephosphor in the conversion element or the lighting device, in particularthe conversion LED. With the lighting device, in particular theconversion LED, in accordance with this embodiment it is advantageouslypossible to obtain many color loci in the blue range of theelectromagnetic spectrum which have not been able to be achievedheretofore.

The lighting devices, in particular the conversion LEDs, of thisembodiment are suitable for example for signal lights, such as bluelights of, for example, police vehicles, ambulances, emergency doctorvehicles or fire department vehicles. Since said signal lights mustfirstly be very bright and secondly be in a specific color locus range(the dominant wavelength is usually between 465 nm and 480 nm), not allblue light sources are suitable for this use. On the other hand,lighting devices, in particular conversion LEDs, comprising the phosphor(Na_(r)K_(1−r))₁(TA)₃(TD)₁(XB)₄:E where 0.4<r≤1, in particularcomprising (Na_(0.5)K_(0.5)) Li₃SiO₄:Eu or(Rb_(r*)Na_(1-r*))₁(TA)₃(TD)₁(XB)₄:E where 0<r*<0.4 in particularcomprising (Rb_(0.25)Na_(0.75)) Li₃SiO₄:Eu, are suitable for suppressingmelatonin production for human beings. (Cs,Na,Rb,Li)₁(TA)₃(TD)₁(XB)₄:E,(Cs,Na,K)₁(TA)₃(TD)₁(XB)₄:E and (Rb,Na,K)₁(TA)₃(TD)₁(XB)₄:E such as forexample (Cs_(0.25)Na_(0.25)Rb_(0.25)Li_(0.25)) Li₃SiO₄:Eu,(Cs_(0.25)Na_(0.5)K_(0.25)) Li₃SiO₄:Eu or(Rb_(0.25)Na_(0.5)K_(0.25))Li₃SiO₄:Eu are likewise suitable for this.TA=Li, TD=Si and XB=O advantageously hold true for the phosphors. Thelighting device, in particular conversion LED, in accordance with thisembodiment can thus be used in a targeted manner to increase thevigilance and/or ability to concentrate. By way of example, they cancontribute to overcoming jetlag more rapidly. Moreover, the phosphor ora lighting device, in particular a conversion LED, comprising thephosphor is suitable for “color on demand” applications, that is to sayfor lighting devices, in particular conversion LEDs, having blue colorloci adapted to consumer desires, for example for realizing certainbrand-specific or product-specific colors, for example in advertising orin the design of the interior fittings for automobiles.

In accordance with at least one embodiment, the lighting device, inparticular the conversion light-emitting diode, is configured to emit ablue or green radiation. The phosphor has the formulaNa_(1−y*)Ca_(y*)Li_(3−2y*)Al_(3y*)Si_(1−y*)O_(4−4y*)N_(4y*):E where0<y*<0.875, advantageously 0<y*≤0.5, particularly advantageously0<y*≤0.3, very particularly advantageously 0<y*≤0.1. By way of example,the phosphor has the formulaNa_(0.97)Ca_(0.03)Li_(2.94)Al_(0.09)Si_(0.97)O_(3.88)N_(0.12):Eu. Thepeak wavelength of the phosphor is in the blue or green spectral range.It is possible for the conversion element to consist of this phosphor orthis phosphor and the matrix material. In particular, the conversionelement or the lighting device, in particular the conversion LED, inaccordance with this embodiment does not have a further phosphor; thephosphor can thus be present, therefore, as sole phosphor in theconversion element or the lighting device, in particular the conversionLED. With the lighting device, in particular the conversion LED, inaccordance with this embodiment it is advantageously possible to obtainmany color loci in the green range of the electromagnetic spectrum. Theconversion light-emitting diode or lighting device of this embodiment issuitable in particular for applications in which a saturated greenemission is required, such as for video projection, for example in thecinema, office or at home, head-up displays, for light sources having anadjustable color rendering index or color temperature, light sourceshaving a spectrum adapted to the application, such as store lighting orFCI lamps (“feeling of contrast index”). FCI lamps are lighting deviceswhich are geared to generating a white light having a particularly highcolor contrast index. Conversion light-emitting diodes or lightingdevices of this embodiment are also suitable for colored spotlights,wall lighting systems or moving spotlights, in particular in stagelighting.

In accordance with at least one embodiment, the lighting device, inparticular the conversion light-emitting diode, is configured to emit ayellow to red radiation. The phosphor has the formulaSr(Si_(0.25)Al_(−1/+r**/2)Li_(7/8−r**/2))₄ (O_(1-r**)N_(r**))₄:E,wherein 0.25≤r**≤1, advantageously 0.25<r**≤0.875, particularlyadvantageously 0.4≤r**≤0.8. Advantageously, E=Eu. By way of example, thephosphor has the formula SrSiAl_(0.84)Li_(2.16)O_(1.32)N_(2.68):Eu²⁺. Inparticular, the primary radiation is completely or almost completelyconverted into the secondary radiation by the phosphor, such that theoverall radiation completely or almost completely corresponds to thesecondary radiation. The peak wavelength of the phosphor is in theyellow to red spectral range. It is possible for the conversion elementto consist of this phosphor or this phosphor and the matrix material. Inparticular, the conversion element or the lighting device, in particularthe conversion LED, in accordance with this embodiment does not have afurther phosphor; the phosphor can thus be present, therefore, as solephosphor in the conversion element or the lighting device, in particularthe conversion LED. With the lighting device, in particular theconversion LED, in accordance with this embodiment it is advantageouslypossible to obtain many color loci in the yellow to red range of theelectromagnetic spectrum.

In accordance with at least one embodiment, the lighting device, inparticular the conversion light-emitting diode, is configured to emit awhite radiation. The phosphor has the following general molecularformula:SrLi_(3−2x**)Al_(1+2x**)O_(4−4x**)N_(4x**):Euwhere 0<x**≤1.0, advantageously 0<x**<0.875, particularly advantageously0.125≤x**<0.875 or 0.125≤x**≤0.5, very particularly advantageously0.125≤x**≤0.45. Advantageously, E=Eu. In this case, it is advantageouslypossible for the conversion element to consist of this phosphor or thisphosphor and the matrix material. In particular, the conversion elementor the lighting device, in particular the conversion LED, in accordancewith this embodiment does not have a further phosphor. The phosphor canthus be present, therefore, as sole phosphor in the conversion elementor the lighting device, in particular the conversion LED. The overallradiation is composed of the primary radiation and the secondaryradiation. In particular, the lighting device, in particular theconversion LED, in accordance with this embodiment emits warm-whiteradiation having a color temperature of less than 3600 K, in particular3400 K±100 K. Advantageously, the color locus of the overall radiationcan be near the Planckian locus. Therefore, this lighting device, inparticular this conversion LED, is suitable in particular for generallighting for example for living spaces.

In accordance with at least one embodiment, the lighting device, inparticular the conversion light-emitting diode, is configured to emit agreen to red radiation. The phosphor has the formulaSrLi_(3−2x**)Al_(1+2x**)O_(4−4x**)N_(4x**):Eu where 0<x**≤1.0,advantageously 0<x**<0.875, particularly advantageously 0.125≤x**<0.875or 0.125≤x**≤0.5, very particularly advantageously 0.125≤x**≤0.45. Thepeak wavelength of the phosphor is in the green to red spectral rangedepending on the proportion of x**. It is possible for the conversionelement to consist of this phosphor or this phosphor and the matrixmaterial. In particular, the conversion element or the lighting device,in particular the conversion LED, in accordance with this embodimentdoes not have a further phosphor; the phosphor can thus be present,therefore, as sole phosphor in the conversion element or the lightingdevice, in particular the conversion LED. With the lighting device, inparticular the conversion LED, in accordance with this embodiment it isadvantageously possible to obtain many color loci in the green to redrange of the electromagnetic spectrum.

In accordance with at least one embodiment, the lighting device, inparticular the conversion light-emitting diode, is configured to emit awhite radiation. The phosphor has the following general molecularformula:(Na_(r)K_(1−r))₁(TA)₃(TD)₁(XB)₄:Ewhere 0.05<r≤0.2, advantageously 0.1<r≤0.2, in particularNa_(0.125)K_(0.875)Li₃SiO₄:Eu. In this case, it is advantageouslypossible for the conversion element to consist of this phosphor or thisphosphor and the matrix material. In particular, the conversion elementor the lighting device, in particular the conversion LED, in accordancewith this embodiment does not have a further phosphor. The phosphor canthus be present, therefore, as sole phosphor in the conversion elementor the lighting device, in particular the conversion LED. The overallradiation is composed of the primary radiation and the secondaryradiation. In particular, the lighting device, in particular theconversion LED, in accordance with this embodiment emits cold-whiteradiation having a color temperature of more than 8000 K. Moreover, itis possible to obtain a high color rendering index without a furtherphosphor being necessary. Therefore, this lighting device, in particularthis conversion LED, is suitable in particular for general lighting, forexample for office spaces.

In accordance with at least one embodiment, the lighting device, inparticular the conversion LED, comprises a filter or filter particlesabsorbing the primary radiation and/or partly the secondary radiation.In particular, the lighting device, in particular conversion LED,comprises a filter or filter particles absorbing the primary radiationand/or partly the secondary radiation if the lighting device, inparticular the conversion LED, is used for the backlighting of displayelements.

In one embodiment, the filters are color filter systems of the colorsred, green and blue.

In one embodiment, the color filter system has a respective full widthat half maximum in the range of 70 to 120 nm for the colors red, green,blue.

The color filter system advantageously comprises a blue filter, a greenfilter and a red filter, which filter the overall radiation to formlight of a first, second and third transmission spectrum.

In one embodiment, the emission of the lighting device, in particular ofthe conversion LED, and the transmission of the color filter system arechosen such that the maxima are at similar wavelengths. As a result,there is only little reabsorption at the color filter system.

In one embodiment, the phosphor(s) is (are) distributed homogeneously inthe conversion element.

In one embodiment, the phosphor(s) are distributed with a concentrationgradient in the conversion element.

In one embodiment, the phosphor having a shorter peak wavelength isdisposed downstream of the phosphor(s) having a longer peak wavelengthin order to reduce absorption losses.

In one embodiment, the phosphor or the phosphors is or are particles ofthe corresponding phosphor.

The particles of the phosphors can have, independently of one another,an average grain size of between 1 μm and 50 μm, advantageously between5 μm and 40 μm, particularly advantageously between 8 μm and 35 μm, veryparticularly advantageously between 8 μm and 30 μm. With these grainsizes, the primary radiation or the secondary radiation isadvantageously scattered little and/or principally in the forwarddirection at these particles, which reduces efficiency losses.

In one embodiment, the conversion element consists of the phosphor andthe matrix material or the phosphors and the matrix material.

In one embodiment, the conversion element is configured as a lamina.

In one embodiment, the lamina has a thickness of 1 μm to 1 mm,advantageously 10 μm to 150 μm, particularly advantageously 25 μm to 100μm.

The layer thickness of the entire lamina can be uniform. In this regard,a constant color locus can be obtained over the entire area of thelamina.

In one embodiment, the conversion element can be a ceramic lamina. Thisshould be understood to mean that the lamina consists ofsintered-together particles of the phosphor or of the phosphors.

In one embodiment, the lamina comprises a matrix material, for exampleglass, in which the phosphor(s) is or are embedded. The lamina can alsoconsist of the matrix material, for example of glass, and thephosphor(s). Silicones, epoxy resins, polysilazanes, polymethacrylatesand polycarbonates and combinations thereof are also possible as matrixmaterials for the lamina.

In accordance with one embodiment, the conversion element is configuredas a lamina arranged above the primary radiation source or the layersequence.

The conversion element shaped as a lamina can be fitted directly on theprimary radiation source or the layer sequence. It is possible for thelamina to completely cover the entire surface, in particular theradiation exit surface, of the primary radiation source or of the layersequence.

The lighting device, in particular the conversion LED, can comprise ahousing. In the housing, a cutout can be present in the center. Theprimary radiation source or the layer sequence can be fitted in thecutout. It is also possible for one or more further primary radiationsources or layer sequences to be fitted in the cutout.

It is possible for the cutout to be filled with a potting that coversthe primary radiation source or the layer sequence. However, the cutoutcan also consist of an air space.

In one embodiment, the conversion element is arranged above the cutoutof the housing. In this embodiment, there is in particular no directand/or positively locking contact between the conversion element and theprimary radiation source or the layer sequence. That is to say thatthere may be a distance between the conversion element and the primaryradiation source or layer sequence. In other words, the conversionelement is disposed downstream of the primary radiation source or thelayer sequence and is irradiated by the primary radiation. A potting oran air gap may then be formed between the conversion element and theprimary radiation source or the layer sequence. This arrangement may bereferred to as “remote phosphor conversion”.

In one embodiment, the conversion element is part of a potting of theprimary radiation source or of the layer sequence or the conversionelement forms the potting.

In one embodiment, the conversion element is configured as a layer. Thelayer can be arranged above the radiation exit surface of the primaryradiation source or of the layer stack or above the radiation exitsurface and the side surfaces of the primary radiation source or of thelayer stack.

The use of a lighting device, in particular of a conversion LED, isspecified. All features of the lighting device and of the conversion LEDare also disclosed for the use thereof, and vice-versa.

The use of a lighting device, in particular of a conversion LED, for thebacklighting of display devices, in particular displays, is specified.By way of example, displays of televisions, such as liquid crystaldisplays, computer monitors, tablets or smartphones are involved.

For the backlighting of display elements, the lighting devices, inparticular conversion LEDs, used must firstly have a high brightness andsecondly cover a large color space. Known filter systems used inconversion LEDs for backlighting consist of three or four color filters(blue, green and red or blue, green, yellow and red). The filtersusually have a full width at half maximum in the range of typically 70to 120 nm. The transmission results from the superposition of the threecolor filters; this results in regions of the visible spectrum in whichcomplete transmission is not achieved. That has the effect that, in thecase of a broadband spectrum of the conversion LED that backlights thecolor filters, a proportion of the emitted light is absorbed by thefilter. In order to obtain the maximum quantity of light from theconversion LED at the display level, therefore, narrowband phosphors arerequired. In order moreover to obtain a high color saturation, it isimportant for the individual emissions of the conversion LEDs to addressspectrally in each case as far as possible only one color of the colorfilter system.

Surprisingly, the lighting devices, in particular conversion LEDs,according to the present disclosure are very well suited to thebacklighting of displays. In particular a lighting device, in particulara conversion LED, having a conversion element comprising the phosphor ofthe formula (Na_(r)K_(1-r))₁(TA)₃(TD)₁(XB)₄:E where 0.2<r≤0.4,advantageously 0.2<r≤0.3, very particularly advantageously r=0.25,(Rb_(r′)Li_(1-r′))₁(TA)₃(TD)₁(XB)₄:E where 0≤r′≤1, advantageously0.25≤r′≤0.75, particularly advantageously 0.4≤r′≤0.6,(K_(1-r″-r′″)Na_(r″)Li_(r′″))₁(TA)₃(TD)₁(XB)₄:E where 0<r″<0.5 and0<r′″<0.5, advantageously 0.1<r″<0.4 and 0.1<r′″<0.4, particularlyadvantageously 0.2<r″<0.3 and 0.2<r″′<0.3,(Cs,Na,K,Li)₁(TA)₃(TD)₁(XB)₄:E, advantageously(Cs_(0.25)Na_(0.25)K_(0.25)Li_(0.25)) (TA)₃(TD)₁(XB)₄:E, or(Rb_(r*)Na_(1-r*))₁(TA)₃(TD)₁(XB)₄:E where 0.4≤r*<1.0, advantageously0.4≤r*≤0.75, particularly advantageously 0.4≤r*≤0.6, very particularlyadvantageously r*=0.5, has proved to be particularly suitable for thebacklighting of display elements since the peak wavelength of thephosphor is in the green spectral range of the electromagnetic spectrumand has a full width at half maximum of less than 50 nm. As a result ofthe small full width at half maximum of the phosphors according to thepresent disclosure, the emission peaks exhibit a very large overlap withthe transmission range of a standard green filter, such that only littlelight is lost and the achievable color space is large.

Lighting devices, in particular conversion LEDs, having a conversionelement comprising the phosphor (Na_(r)K_(1-r))₁(TA)₃(TD)₁(XB)₄:E where0.05<r≤0.2, advantageously 0.1<r≤0.2, are also suitable for thebacklighting of displays.

The use of a lighting device, in particular a conversion LED, in warninglights and flashing lights in motor vehicles is specified. The lightingdevice, in particular the conversion light-emitting diode, is configuredto emit an orange or yellow-orange radiation. Advantageously, thephosphor has the formulaNa_(1−y**)Eu_(y**)Li_(3−2y**)Al_(3y**)Si_(1−y**)O_(4−4y**)N_(4y**):Eu,wherein 0.1≤y**≥0.4, 0.15≤y**≤0.35 or 0.2≤y**≤0.3.

The use of a lighting device, in particular a conversion LED, in bluelight sources for reducing melatonin production or for color-on-demandapplications is specified. The lighting device, in particular theconversion light-emitting diode, is configured to emit a blue radiation.Advantageously, the phosphor has the formula(Na_(r)K_(1-r))₁(TA)₃(TD)₁(XB)₄:E where 0.4<r≤1, advantageously0.45<r≤1, very particularly advantageously r=0.5. Advantageously, TA=Li,TD=Si and XB=O. By way of example, the phosphor has the formula(Na_(0.5)K_(0.5))Li₃SiO₄:Eu. Alternatively, the phosphor has the formula(Rb_(r*)Na_(1-r*))₁(TA)₃(TD)₁(XB)₄:E, wherein 0<r*<0.4, advantageously0.1≤r*≤0.35, particularly advantageously 0.2≤r*≤0.3, very particularlyadvantageously r*=0.25. By way of example, the phosphor has the formula(Rb_(0.25)Na_(0.75)) Li₃SiO₄:Eu. Alternatively, the phosphor has theformula (Cs,Na,Rb,Li)₁(TA)₃(TD)₁(XB)₄:E, (Cs,Na,K)₁(TA)₃(TD)₁(XB)₄:E or(Rb,Na,K)₁(TA)₃(TD)₁(XB)₄:E, for example(Cs_(0.25)Na_(0.25)Rb_(0.25)Li_(0.25)) Li₃SiO₄:Eu,(Cs_(0.25)Na_(0.5)K_(0.25)) Li₃SiO₄:Eu or (Rb_(0.25)Na_(0.5)K_(0.25))Li₃SiO₄:Eu. The peak wavelength of the phosphor is in the blue spectralrange.

Vigilance and/or the ability to concentrate can be increased by reducingmelatonin production.

The use of a lighting device, in particular a conversion LED, forgeneral lighting is specified. The lighting device, in particular theconversion light-emitting diode, is configured to emit a whiteradiation. In particular, warm-white radiation having a colortemperature of less than 3500 K, advantageously less than 3000 K, isinvolved.

For general lighting, the phosphor in this case has for example theformula (Na_(r)K_(1−r))₁(TA)₃(TD)₁(XB)₄:E where 0≤r≤0.05, advantageouslyr=0. Advantageously, TA=Li, TD=Si and XB=O. By way of example, thephosphor is KLi₃SiO₄:Eu. The phosphor exhibits very broadband emissionfrom the blue to red spectral range, thus giving rise to a white-coloredluminous impression. The lighting device, in particular the conversionLED, in accordance with this embodiment emits a warm-white radiationhaving a color temperature of less than 3500 K, in particular less than3000 K.

For general lighting, the phosphor can also have the following formula(Na_(r)K_(1-r))₁(TA)₃(TD)₁(XB)₄:Ewhere 0.4<r≤1, advantageously 0.45<r≤1, very particularly advantageouslyr=0.5 or 1. Advantageously, TA=Li, TD=Si and XB=O. By way of example,the phosphor has the formula NaLi₃SiO₄:Eu or(Na_(0.5)K_(0.5))Li₃SiO₄:Eu. Alternatively, the phosphor can have theformula (Rb_(r*)Na_(1-r*))₁(TA)₃(TD)₁(XB)₄:E, wherein 0<r*<0.4,advantageously 0.1≤r*≤0.35, particularly advantageously 0.2≤r*≤0.3, veryparticularly advantageously r*=0.25. By way of example, the phosphor hasthe formula (Rb_(0.25)Na_(0.75)) Li₃SiO₄:Eu. Alternatively, the phosphorhas the formula (Cs,Na,Rb,Li)₁(TA)₃(TD)₁(XB)₄:E,(Cs,Na,K)₁(TA)₃(TD)₁(XB)₄:E or (Rb,Na,K)₁(TA)₃(TD)₁(XB)₄:E, for example(Cs_(0.25)Na_(0.25)Rb_(0.25)Li_(0.25)) Li₃SiO₄:Eu,(Cs_(0.25)Na_(0.5)K_(0.25)) Li₃SiO₄:Eu or (Rb_(0.25)Na_(0.5)K_(0.25))Li₃SiO₄:Eu. The peak wavelengths of these phosphors are advantageouslyin the blue spectral range, in particular in the range of between 450 nmand 500 nm. The conversion element comprises a second and a thirdphosphor, wherein the second phosphor is configured partly to convertthe electromagnetic primary radiation into an electromagnetic secondaryradiation in the red spectral range and the third phosphor is configuredto convert the electromagnetic primary radiation into an electromagneticsecondary radiation in the green spectral range during operation of thelighting device.

For general lighting, the phosphor can also have the following formulaNa_(1−y*)Ca_(y*)Li_(3−2y)Al_(3y*)Si_(1−y*)O_(4−4y*)N_(4y*):E0<y*≤0.875, advantageously 0<y*≤0.5, particularly advantageously0<y*≤0.3, very particularly advantageously 0<y*≤0.1. The peak wavelengthof the phosphor is advantageously in the blue or green spectral range.The conversion element comprises a second and a third phosphor, whereinthe second phosphor is configured partly to convert the electromagneticprimary radiation into an electromagnetic secondary radiation in the redspectral range and the third phosphor is configured to convert theelectromagnetic primary radiation into an electromagnetic secondaryradiation in the green spectral range during operation of the lightingdevice.

In accordance with at least one embodiment, the display device is adisplay, for example of a television, of a smartphone, or a computermonitor or of a tablet.

In accordance with at least one embodiment, the lighting device, inparticular the conversion LED, has a conversion element comprising thephosphor of the formula (Na_(r)K_(1-r))₁(TA)₃(TD)₁(XB)₄:E where0.2<r≤0.4, advantageously 0.2<r≤0.3, particularly advantageously r=0.25or (Rb_(r′)Li_(1-r′))₁(TA)₃(TD)₁(XB)₄:E where 0≤r′≤1, advantageously0.25≤r′≤0.75, particularly advantageously 0.4≤r′≤0.6, very particularlyadvantageously r′=0.5, (K_(1−r″−r′″)Na_(r″)Li_(r′″))₁(TA)₃(TD)₁(XB)₄:Ewhere 0<r″<0.5 and 0<r′″<0.5, advantageously 0.1<r″<0.4 and 0.1<r″′<0.4,particularly advantageously 0.2<r″<0.3 and 0.2<r″′<0.3,(Cs,Na,K,Li)₁(TA)₃(TD)₁(XB)₄:E, advantageously(Cs_(0.25)Na_(0.25)K_(0.25)Li_(0.25)) (TA)₃(TD)₁(XB)₄:E or(Rb_(r*)Na_(1-r*))₁(TA)₃(TD)₁(XB)₄:E where 0.4≤r*<1.0, advantageously0.4≤r*≤0.75, particularly advantageously 0.4≤r*≤0.6, very particularlyadvantageously r*=0.5. The conversion element comprises a secondphosphor configured partly to convert the electromagnetic primaryradiation into an electromagnetic secondary radiation that is in the redspectral range of the electromagnetic spectrum during operation of thelighting device.

EXEMPLARY EMBODIMENTS

The first exemplary embodiment (Al) of the phosphor according to thepresent disclosure has the molecular formula NaLi₃SiO₄:Eu²⁺ (2 mol %Eu²⁺ relative to the substance amount of Na) and is produced as follows:Na₂CO₃, Li₂CO₃, SiO₂ and Eu₂O₃ are melted in a stoichiometric ratiocorresponding to the molecular formula in an open nickel crucible. Theweighed-in quantities of the starting materials are found in table 1below. The nickel crucible with the mixed starting materials is heatedfor one hour to approximately 1000° C. under a forming gas atmosphere(N₂:H₂=92.5:7.5) and then cooled. Further heating under the same forminggas atmosphere and to temperatures below the melting point of thephosphor can be carried out in order to further improve the opticalproperties of the phosphor.

TABLE 1 Starting Substance amount/ material mmol Mass/g Na₂CO₃ 21.822.313 Li₂CO₃ 66.21 4.892 SiO₂ 43.94 2.640 Eu₂O₃ 0.44 0.155

The starting materials of the phosphor are commercially available,stable and moreover very inexpensive. The synthesis at comparatively lowtemperatures makes the phosphor very inexpensive to produce and, as aresult, also economically attractive.

The phosphor of the first exemplary embodiment (AB1) exhibits anemission in the blue spectral range of the electromagnetic spectrum.

The second exemplary embodiment (AB2) of the phosphor according to thepresent disclosure has the molecular formula KLi₃SiO₄:Eu²⁺ (2 mol % Eu²⁺relative to the substance amount of K) and is produced as follows:K₂CO₃, Li₂CO₃, SiO₂ and Eu₂O₃ are melted in a stoichiometric ratiocorresponding to the molecular formula in an open nickel crucible. Theweighed-in quantities of the starting materials are found in table 2below. The nickel crucible with the mixed starting materials is heatedfor one hour to approximately 1000° C. under a forming gas atmosphere(N₂:H₂=92.5:7.5) and then cooled. Further heating under the same forminggas atmosphere and to temperatures below the melting point of thephosphor can be carried out in order to further improve the opticalproperties of the phosphor.

TABLE 2 Starting Substance amount/ material mmol Mass/g K₂CO₃ 40.785.636 Li₂CO₃ 123.71 9.141 SiO₂ 82.10 4.933 Eu₂O₃ 0.82 0.290

The phosphor of the second exemplary embodiment (AB2) exhibits a wideemission from the blue to red spectral range of the electromagneticspectrum and thus emits white, in particular warm-white, radiationhaving a color temperature of less than 3500 K.

The third exemplary embodiment (AB3) of the phosphor according to thepresent disclosure has the molecular formula(Na_(0.5)K_(0.5))Li₃SiO₄:Eu²⁺ (2 mol % Eu²⁺ relative to the substanceamount of Na and K) or NaKLi₆Si₂O₈:Eu²⁺ and is produced as follows:K₂CO₃, Na₂CO₃, Li₂CO₃, SiO₂ and Eu₂O₃ are melted in a stoichiometricratio corresponding to the molecular formula in an open nickel crucible.The weighed-in quantities of the starting materials are found in table 3below. The nickel crucible with the mixed starting materials is heatedfor one hour to eight hours to 800° C. to 1100° C. under a forming gasatmosphere (N₂:H₂=92.5:7.5) and then cooled. Further heating under thesame forming gas atmosphere and to temperatures below the melting pointof the phosphor can be carried out in order to further improve theoptical properties of the phosphor.

TABLE 3 Starting Substance amount/ material mmol Mass/g Na₂CO₃ 10.651.129 K₂CO₃ 10.44 1.443 Li₂CO₃ 63.97 4.727 SiO₂ 42.46 2.551 Eu₂O₃ 0.430.150

The phosphor of the third exemplary embodiment (AB3) exhibits anemission in the blue spectral range of the electromagnetic spectrum.

The fourth exemplary embodiment (AB4) of the phosphor according to thepresent disclosure has the molecular formula(Na_(0.25)K_(0.75))Li₃SiO₄:Eu²⁺ (2 mol % Eu²⁺ relative to the substanceamount of Na and K) or NaK₃Li₁₂Si₄O₁₆:Eu²⁺ and is produced as follows:K₂CO₃, Na₂CO₃, Li₂CO₃, SiO₂ and Eu₂O₃ are melted in a stoichiometricratio corresponding to the molecular formula in an open nickel crucible.The weighed-in quantities of the starting materials are found in table 4below. The nickel crucible with the mixed starting materials is heatedfor four hours to 900° C. to 1100° C. under a forming gas atmosphere(N₂:H₂=92.5:7.5) and then cooled. Further heating under the same forminggas atmosphere and to temperatures below the melting point of thephosphor can be carried out in order to further improve the opticalproperties of the phosphor.

TABLE 4 Starting Substance amount/ material mmol Mass/g Na₂CO₃ 5.240.555 K₂CO₃ 15.50 2.142 Li₂CO₃ 62.90 4.648 SiO₂ 41.75 2.508 Eu₂O₃ 0.420.147

The phosphor of the fourth exemplary embodiment (AB4) exhibits anemission in the green spectral range of the electromagnetic spectrum.

The fifth exemplary embodiment (AB5) of the phosphor according to thepresent disclosure has the molecular formula (Rb_(0.5)Li_(0.5))Li₃SiO₄:Eu²⁺ (2 mol % Eu²⁺ relative to the substance amount of(Rb_(0.5)Li_(0.5))) or RbLiLi₆Si₂O₈:Eu²⁺ and is produced as follows:Rb₂CO₃, Li₂CO₃, SiO₂ and Eu₂O₃ are melted in a stoichiometric ratiocorresponding to the molecular formula in an open nickel crucible. Theweighed-in quantities of the starting materials are found in table 5below. The nickel crucible with the mixed starting materials is heatedfor four hours to approximately 1000° C. under a forming gas atmosphere(N₂:H₂=92.5:7.5) and then cooled. Afterward, the product obtained isground and a green powder is obtained.

Further heating under the same forming gas atmosphere and totemperatures below the melting point of the phosphor can be carried outin order to further improve the optical properties of the phosphor.

TABLE 5 Starting Substance amount/ material mmol Mass/g Rb₂CO₃ 17.053.937 Li₂CO₃ 52.30 3.864 SiO₂ 34.56 2.076 Eu₂O₃ 0.35 0.122

The phosphor of the fifth exemplary embodiment (AB5) exhibits anemission in the green spectral range of the electromagnetic spectrum.

The sixth exemplary embodiment (AB6) of the phosphor according to thepresent disclosure has the molecular formulaNa_(1−y*)Ca_(y*)Li_(3−2y*)Al_(3y*)Si_(1−y*)O_(4−4y*)N_(4y*):Eu (wherey*=0.03; Eu²⁺ approximately 2 mol % relative to the substance amount ofNa and Ca) and is produced as follows: CaO, NaF, NiN₃, Li₂O, LiAlH₄,AlF₃, SiO₂ and EuF₃ are heated in a stoichiometric ratio correspondingto the molecular formula to a maximum of 950° C. in a welded shuttantalum ampoule. During the heating or firing process, the ampoule issituated in an evacuated glass tube in order to avoid oxidation of theampoule (reduced stability) and hence bursting, which results from thevapor pressure of evaporated starting materials during heating. Aftercooling to room temperature, individual crystals of the phosphor can beisolated from byproducts and be structurally and optically examined. Theweighed-in quantities of the starting materials are found in table 6below.

TABLE 6 Starting material Mass/mg CaO 7.01 NaF 15.75 LiN₃ 8.15 Li₂O21.51 LiAlH₄ 9.49 AlF₃ 10.50 SiO₂ 22.53 EuF₃ 2.09

The synthesis at comparatively low temperatures makes the phosphor veryinexpensive to produce and, as a result, also economically attractive.By means of energy dispersive X-ray spectroscopy on single crystals ofthe phosphor, an average Ca proportion of 3 mol % based on the totalsubstance amount of Na and Ca and a nitrogen proportion of 3 mol %relative to the total substance amount of nitrogen and oxygen weredetermined, which accords with the formulaNa_(0.97)Ca_(0.03)Li_(2.94)Al_(0.09)Si_(0.97)O_(3.88)N_(0.12):Eu.

The phosphor of the sixth exemplary embodiment (AB6) exhibits anemission in the blue-green spectral range of the electromagneticspectrum.

The seventh exemplary embodiment (AB7) of the phosphor according to thepresent disclosure has the molecular formula(Na_(0.25)K_(0.50)Li_(0.25)) Li₃SiO₄:Eu²⁺ or NaK₂Li(Li₃SiO₄)₄:Eu²⁺ andis produced as follows: K₂CO₃, Na₂CO₃, Li₂CO₃, SiO₂ and Eu₂O₃ are mixedin a stoichiometric ratio corresponding to the molecular formula in anopen nickel crucible. The weighed-in quantities of the startingmaterials are found in table 7 below. The nickel crucible with the mixedstarting materials is heated for four hours to approximately 750° C.under a forming gas atmosphere (N₂:H₂=92.5:7.5) and then cooled. Furtherheating under the same forming gas atmosphere and to temperatures belowthe melting point of the phosphor can be carried out in order to furtherimprove the optical properties of the phosphor. After cooling, anagglomerate of light green crystals is obtained, which are separatedinto individual crystals by grinding for example in an agate mortar.

TABLE 7 Starting Substance amount/ material mmol Mass/g Na₂CO₃ 1.3770.146 K₂CO₃ 9.420 1.302 Li₂CO₃ 77.192 5.704 SiO₂ 46.117 2.771 Eu₂O₃0.220 0.078

The phosphor of the seventh exemplary embodiment (AB7) exhibits anemission in the green spectral range of the electromagnetic spectrum. Bymeans of single crystal diffractometry, the molecular formula(Na_(0.25)K_(0.50)Li_(0.25))Li₃SiO₄:Eu²⁺ can be allocated to thephosphor.

The eighth exemplary embodiment (AB8) of the phosphor according to thepresent disclosure has the molecular formula (Rb_(0.5)Na_(0.5))Li₃SiO₄:Eu²⁺ or RbNaLi₆Si₂O₈:Eu²⁺ and is produced as follows: Rb₂CO₃,Na₂CO₃, Li₂CO₃, SiO₂ and Eu₂O₃ are mixed in a stoichiometric ratiocorresponding to the molecular formula in an open nickel crucible. Theweighed-in quantities of the starting materials are found in table 8below. The nickel crucible with the mixed starting materials is heatedfor one to eight hours to between 700° C. and 1000° C. under a forminggas atmosphere (N₂:H₂=92.5:7.5) and then cooled. The product obtained isthen ground and a green powder is obtained.

Further heating under the same forming gas atmosphere and totemperatures below the melting point of the phosphor can be carried outin order to further improve the optical properties of the phosphor.

TABLE 8 Starting Substance amount/ material mmol Mass/g Rb₂CO₃ 9.642.226 Na₂CO₃ 8.77 0.929 Li₂CO₃ 59.2 4.371 SiO₂ 39.1 2.348 Eu₂O₃ 0.3580.126

The phosphor of the eighth exemplary embodiment (AB8) exhibits anemission in the green spectral range of the electromagnetic spectrum.

The ninth exemplary embodiment (AB9) of the phosphor according to thepresent disclosure has the molecular formula (Rb_(0.25)Na_(0.75))Li₃SiO₄:Eu²⁺ or RbNa₃Li₁₂Si₄O₁₆:Eu²⁺ and is produced as follows: Rb₂CO₃,Na₂CO₃, Li₂CO₃, SiO₂ and Eu₂O₃ are mixed in a stoichiometric ratiocorresponding to the molecular formula in an open nickel crucible. Theweighed-in quantities of the starting materials are found in table 9below. The nickel crucible with the mixed starting materials is heatedfor one to eight hours to between 700° C. and 1000° C. under a forminggas atmosphere (N₂:H₂=92.5:7.5) and then cooled. The product obtained isthen ground and a green powder is obtained.

Further heating under the same forming gas atmosphere and totemperatures below the melting point of the phosphor can be carried outin order to further improve the optical properties of the phosphor.

TABLE 9 Starting Substance amount/ material mmol Mass/g Rb₂CO₃ 5.5211.275 Na₂CO₃ 14.96 1.586 Li₂CO₃ 60.28 4.454 SiO₂ 44.10 2.650 Eu₂O₃ 0.10.035

The phosphor of the ninth exemplary embodiment (AB9) exhibits anemission in the blue spectral range of the electromagnetic spectrum.

The tenth exemplary embodiment (AB10) of the phosphor according to thepresent disclosure has the molecular formulaSr(Si_(0.25)Al_(−1/8+r**/2)Li_(7/8−r**/2))₄ (O_(1-r**)N_(r**))₄ wherer**=0.67 and thus SrSiAl_(0.84)Li_(2.16)O_(1.32)N_(2.68):Eu²⁺ and isproduced as follows: NaLi₃SiO₄, SrO, LiAlH₄ and Eu₂O₃ are mixed in anopen nickel crucible. The weighed-in quantities of the startingmaterials are found in table 10 below. The nickel crucible with themixed starting materials is heated for one to eight hours,advantageously 2 to six hours, very particularly advantageously for fourhours, to a temperature between 800° C. and 1000° C., advantageously900° C., under a forming gas atmosphere (N₂:H₂=92.5:7.5) in a tubefurnace and then cooled.

Further heating under the same forming gas atmosphere and totemperatures below the melting point of the phosphor can be carried outin order to further improve the optical properties of the phosphor.

TABLE 10 Starting Substance amount/ material mmol Mass/g NaLi₃SiO₄ 31.424.270 SrO 23.70 2.456 LiAlH₄ 77.12 2.922 Eu₂O₃ 1.00 0.352

The phosphor of the tenth exemplary embodiment (AB10) exhibits anemission in the yellow or yellow-orange spectral range of theelectromagnetic spectrum. The composition of the tenth exemplaryembodiment was determined by means of energy dispersive X-rayspectroscopy on single crystals and single crystal diffractometry.

The eleventh exemplary embodiment (AB11) of the phosphor according tothe present disclosure has the molecular formulaNa_(1−y**)Eu_(y*)Li_(3−2y**)Al_(3y**)Si_(1−y**)O_(4−4y**)N_(4y**):Euwhere y**=0.2224 and is produced as follows: CaO, LiF, LiN₃, Li₂O,LiAlH₄, SiO₂ and EuF₃ are heated to a maximum of 900° C. in a weldedshut tantalum ampoule. During the heating or firing process, the ampouleis situated in an evacuated glass tube in order to avoid oxidation ofthe ampoule (reduced stability) and hence bursting, which results fromthe vapor pressure of evaporated starting materials during heating.After cooling to room temperature, individual orange crystals of thephosphor can be isolated from byproducts and be structurally andoptically examined. The weighed-in quantities of the starting materialsare found in table 11 below.

TABLE 11 Starting material Mass/mg Na₂O 11.02 LiF (Flux) 10 LiN₃ 11.61Li₂O 17.72 LiAlH₄ 13.50 SiO₂ 21.37 EuF₃ 24.78

The phosphor of the eleventh exemplary embodiment (AB11) exhibits anemission in the yellow-orange spectral range of the electromagneticspectrum.

The twelfth exemplary embodiment (AB12) of the phosphor according to thepresent disclosure has the molecular formulaSrLi_(3−2x**)Al_(1+2x**)O_(4−4x**)N_(4x**):Eu where x**=0.2014 and isproduced as follows: SrAl₂O₄:Eu and LiN₃ are heated to a maximum of 900°C. in a welded shut tantalum ampoule. During the heating or firingprocess, the ampoule is situated in an evacuated glass tube in order toavoid oxidation of the ampoule (reduced stability) and hence bursting,which results from the vapor pressure of evaporated starting materialsduring heating. After cooling to room temperature, individualyellow/green crystals of the phosphor can be isolated from byproductsand be structurally and optically examined. The weighed-in quantities ofthe starting materials are found in table 12 below.

TABLE 12 Starting material Mass/mg SrAl₂O₄:Eu 30.64 LiN₃ 22.06

The phosphor can be produced at comparatively low temperatures, below1000° C., which makes possible a cost-saving synthesis.

The phosphor of the twelfth exemplary embodiment (AB12) exhibits anemission in the green to yellow spectral range of the electromagneticspectrum.

Further exemplary embodiments of the phosphor having the molecularformula SrLi_(3−2x**)Al_(1+2x**)O_(4−4x**)N_(4x**):Eu are produced bymixing the starting materials in accordance with table 13 below in anopen nickel crucible. The nickel crucible with the mixed startingmaterials is heated for one to 12 hours, advantageously 4 to 8 hours, toa temperature of between 800° C. and 1200° C., advantageously 900° C.,under a forming gas atmosphere (N₂:H₂=92.5:7.5) under atmosphericpressure or slightly reduced pressure in a tube furnace and is thencooled. After cooling to room temperature, individual yellow/greencrystals can be isolated.

TABLE 13 Exemplary Starting Substance embodiment x** materialamount/mmol Mass/g AB12-1 0.125 SrO 70.00 7.253 Al₂O₃ 17.67 1.802 Li₃N23.57 0.821 Eu₂O₃ 0.3524 0.124 AB12-2 0.1375 SrO 75.17 7.789 Al₂O₃ 15.181.548 Li₃N 15.19 0.529 Eu₂O₃ 0.3808 0.134 AB12-3 0.17 SrO 63.22 6.551Al₂O₃ 43.00 4.385 Li₂CO₃ 21.50 1.589 Li₃N 64.51 2.247 Eu₂O₃ 0.6450 0.227AB12-4 0.20 SrO 69.44 7.195 Al₂O₃ 49.60 5.057 Li₂CO₃ 7.092 0.524 Li₃N56.68 1.974 Eu₂O₃ 0.7075 0.249 AB12-5 0.24 SrO 70.48 7.303 Al₂O₃ 48.904.986 AlN 8.636 0.354 Li₃N 60.40 2.104 Eu₂O₃ 0.7189 0.253 AB12-6 0.28SrO 70.04 7.258 Al₂O₃ 44.79 4.567 AlN 21.91 0.898 Li₃N 58.14 2.025 Eu₂O₃0.7161 0.252 AB12-7 0.34 SrO 69.41 7.192 Al₂O₃ 38.72 3.948 AlN 41.551.703 Li₃N 54.78 1.908 Eu₂O₃ 0.7075 0.249 AB12-8 0.44 SrO 68.37 7.085Al₂O₃ 28.83 2.940 AlN 73.48 3.012 Li₃N 49.30 1.717 Eu₂O₃ 0.6990 0.246

The thirteenth exemplary embodiment (AB13) of the phosphor according tothe present disclosure has the molecular formula(Cs_(0.25)Na_(0.25)K_(0.25)Li_(0.25)) Li₃SiO₄:Eu²⁺ and is producedanalogously to the eighth exemplary embodiment. The starting materialsare indicated in table 14 below.

TABLE 14 Starting Substance amount/ material mmol Mass/g Cs₂CO₃ 4.751.547 Na₂CO₃ 5.16 0.547 Li₂CO₃ 62.1 4.585 K₂CO₃ 5.16 0.713 SiO₂ 41.02.463 Eu₂O₃ 0.412 0.145

The phosphor of the thirteenth exemplary embodiment (AB13) exhibits anemission in the green spectral range of the electromagnetic spectrum.

The fourteenth exemplary embodiment (AB14) of the phosphor according tothe present disclosure has the molecular formula(Cs_(0.25)Na_(0.50)K_(0.25))Li₃SiO₄:Eu²⁺ and is produced analogously tothe eighth exemplary embodiment. The starting materials are indicated intable 15 below.

TABLE 15 Starting Substance amount/ material mmol Mass/g Cs₂CO₃ 4.501.466 Na₂CO₃ 9.78 1.037 Li₂CO₃ 58.8 4.347 K₂CO₃ 4.89 0.676 SiO₂ 38.92.336 Eu₂O₃ 0.392 0.138

The phosphor of the fourteenth exemplary embodiment (AB14) exhibits anemission in the blue spectral range of the electromagnetic spectrum.

The fifteenth exemplary embodiment (AB15) of the phosphor according tothe present disclosure has the molecular formula(Rb_(0.25)Na_(0.50)K_(0.25))Li₃SiO₄:Eu²⁺ and is produced analogously tothe eighth exemplary embodiment. The starting materials are indicated intable 16 below.

TABLE 16 Starting Substance amount/ material mmol Mass/g Rb₂CO₃ 4.701.086 Na₂CO₃ 10.2 1.083 Li₂CO₃ 61.5 4.541 K₂CO₃ 5.11 0.706 SiO₂ 40.62.440 Eu₂O₃ 0.409 0.144

The phosphor of the fifteenth exemplary embodiment (AB15) exhibits anemission in the blue spectral range of the electromagnetic spectrum.

The sixteenth exemplary embodiment (AB16) of the phosphor according tothe present disclosure has the molecular formula(Rb_(0.25)Na_(0.25)Cs_(0.25)Li_(0.25)) Li₃SiO₄:Eu²⁺ and is producedanalogously to the eighth exemplary embodiment. The starting materialsare indicated in table 17 below.

TABLE 17 Starting Substance amount/ material mmol Mass/g Rb₂CO₃ 4.491.036 Cs₂CO₃ 4.48 1.461 Na₂CO₃ 9.34 0.990 Li₂CO₃ 56.2 4.151 SiO₂ 37.12.230 Eu₂O₃ 0.375 0.132

The phosphor of the sixteenth exemplary embodiment (AB16) exhibits anemission in the blue spectral range of the electromagnetic spectrum.

The seventeenth exemplary embodiment (AB17) of the phosphor according tothe present disclosure has the molecular formula(Na_(0.125)K_(0.875))Li₃SiO₄:Eu²⁺ or NaK₇ (Li₃SiO₄):Eu²⁺ and is producedas follows: K₂CO₃, Na₂CO₃, Li₂CO₃, SiO₂ and Eu₂O₃ are mixed in astoichiometric ratio corresponding to the molecular formula in an opennickel crucible. The weighed-in quantities of the starting materials arefound in table 18 below. The nickel crucible with the mixed startingmaterials is heated for four hours to 1000° C. under a forming gasatmosphere (N₂:H₂=92.5:7.5) and is then cooled at a constant coolingrate to 300° C. The furnace is switched off and, after cooling to roomtemperature, yellow-green single crystals are isolated.

TABLE 18 Starting material Mass/mg Na₂CO₃ 25.97 K₂CO₃ 101.58 Li₂CO₃221.67 SiO₂ 120.17 Eu₂O₃ 7.04

The phosphor of the seventeenth exemplary embodiment (AB17) exhibits anemission in the blue-green and in the yellow-orange spectral range ofthe electromagnetic spectrum.

Further advantageous embodiments and developments of the presentdisclosure are evident from the exemplary embodiments described below inassociation with the figures.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, like reference characters generally refer to the sameparts throughout the different views. The drawings are not necessarilyto scale, emphasis instead generally being placed upon illustrating theprinciples of the disclosed embodiments. In the following description,various embodiments described with reference to the following drawings,in which:

FIGS. 1A, 1B, 1BA, 1BB, 1C, 1D, 1E, 1F show a selection of possibleelectroneutral molecular formulae of substitution experiments.

FIGS. 2, 13, 23, 38, 63, 68, 74, 82, 83, 92, 93, 102, 103, 105, 112, 118b, 129, 131, 133, 135, 152 b, 154, 161, 163 show emission spectra ofexemplary embodiments of the phosphor according to the presentdisclosure.

FIGS. 3, 14, 24, 39, 64, 84, 94, 104, 130, 132, 134, 136 show theKubelka-Munk functions for exemplary embodiments of the phosphoraccording to the present disclosure.

FIGS. 4, 43, 66, 70, 76, 86, 96, 121, 123 show a comparison of opticalproperties of an exemplary embodiment of the phosphor according to thepresent disclosure with comparative examples.

FIGS. 5, 6, 44, 67, 69, 75, 85, 95, 122 show a comparison of emissionspectra of an exemplary embodiment with comparative examples.

FIG. 7 shows a comparison of the Kubelka-Munk function of an exemplaryembodiment with comparative examples.

FIGS. 8, 18, 25, 71, 77, 78, 88, 97, 107, 114, 137, 138, 139, 140, 160,171, 172, 173 show excerpts from the crystal structure for exemplaryembodiments of the phosphor according to the present disclosure.

FIGS. 9, 19, 40, 65, 111, 118 a, 177 show X-ray diffraction powderdiffractograms using copper K_(α1) radiation or molybdenum K_(α1)radiation.

FIGS. 10, 20, 26, 89, 98, 141, 142, 143, 144 show Rietveld refinementsof X-ray powder diffractograms of exemplary embodiments of the phosphoraccording to the present disclosure.

FIGS. 11, 12, 21, 22, 27, 28, 72, 73, 79, 80, 81, 90, 91, 99, 100, 108,109, 110, 115, 116, 117, 126, 127, 128, 145-151, 152 a, 158, 159, 174,175, 176 show characteristic properties of exemplary embodiments of thephosphor according to the present disclosure.

FIGS. 15, 16, 124 show comparisons of emission spectra of a conversionLED with an exemplary embodiment of the phosphor according to thepresent disclosure with comparative examples.

FIGS. 17, 125, 164, 167 show a comparison of optical properties of aconversion LED with an exemplary embodiment of the phosphor according tothe present disclosure with comparative examples.

FIG. 29 shows a comparison of emission spectra of an exemplaryembodiment with comparative examples and the sensitivity curve formelatonin production.

FIG. 30 shows the overlap of emission spectra of various phosphors andvarious blue-emitting LEDs with the sensitivity curve for melatoninproduction.

FIGS. 31, 120, 165 show color loci of various phosphors in the CIEstandard diagram (1931).

FIGS. 32, 33, 34 show comparisons of the color purity at differentdominant wavelengths of the primary radiation of an exemplary embodimentwith comparative examples.

FIGS. 35, 36, 37, 166, 168 show simulated LED spectra at variousexcitation wavelengths.

FIG. 41 shows the reflection positions and the relative intensity of thereflections of the X-ray diffraction powder diffractogram of anexemplary embodiment of the phosphor according to the presentdisclosure.

FIGS. 42, 87, 101 show the thermal quenching behavior of an exemplaryembodiment of the phosphor according to the present disclosure incomparison with the conventional phosphor.

FIG. 45 shows the coverage of the color space rec2020 by differentcombinations of green and red phosphor.

FIGS. 46 to 53 show graphical representations of the coverage of thecolor space rec2020 by different combinations of green and red phosphor.

FIGS. 54A, 54AA, 54AB, 54AC, 54AD, 54B, 54BA, 54BB, 54BC, 54BD, 54C,54CA, 54CB, 54CC, and 54CD show the coverage of various standard colorspaces and color loci of filtered spectra of different combinations ofgreen and red phosphor.

FIGS. 55 to 58 show the spanned color spaces of filtered spectra withdifferent combinations of green and red phosphor upon excitation with aprimary radiation λdom=448 nm.

FIGS. 59 to 62 show the simulated emission spectra of conversion LEDswith different combinations of green and red phosphor.

FIGS. 178 to 180 show schematic side views of various embodiments ofconversion LEDs described here.

FIGS. 106, 113, 119, 153, 155, 162 show optical properties of exemplaryembodiments.

FIGS. 156 and 157 show the dependence of the peak wavelength on the cellvolume of a unit cell.

FIGS. 169 and 170 show spanned color spaces of the filtered overallradiation of various conversion LEDs.

DETAILED DESCRIPTION

In the following description, numerous specific details are given toprovide a thorough understanding of embodiments. The embodiments may bepracticed without one or several specific details, or with othermethods, components, materials, etc. In other instances, well-knownstructures, materials, or operations are not shown or described indetail to avoid obscuring aspects of the embodiments.

Reference throughout this specification to “one embodiment” or “anembodiment” means that a particular feature, structure, orcharacteristic described in connection with the embodiment is includedin at least one embodiment. Thus, the appearances of the phrases “in oneembodiment” or “in an embodiment” in various places throughout thisspecification are not necessarily all referring to the same embodiment.Furthermore, the particular features, structures, or characteristics maybe combined in any suitable manner in one or more embodiments.

FIGS. 1A, 1B, 1C, 1D, 1E and 1F show tables with possible electroneutralphosphors which are achievable by substitution experiments, analogouslyto the general molecular formula (MA)_(a)(MB)_(b)(MC)_(c)(MD)_(d)(TA)_(e)(TB)_(f)(TC)_(g)(TD)_(h)(TE)_(i)(TF)_(j)(XA)_(k)(XB)_(l)(XC)_(m)(XD)_(n).The substitutions shown are merely by way of example, othersubstitutions are likewise possible. The activator E is illustrated ineach case only in the general formula and not in the concreteembodiments, but is nevertheless also present in the concreteembodiments.

FIG. 2 illustrates the emission spectrum of the first exemplaryembodiment AB1 of the phosphor according to the present disclosurehaving the molecular formula NaLi₃SiO₄. The wavelength in nanometers isplotted on the x-axis and the emission intensity in percent is plottedon the y-axis. For measuring the emission spectrum, the phosphoraccording to the present disclosure was excited with primary radiationhaving a wavelength of 400 nm. The phosphor has a full width at halfmaximum of 32 nm or 1477 cm⁻¹ and a dominant wavelength of 473 nm; thepeak wavelength is approximately 469 nm.

FIG. 3 shows a normalized Kubelka-Munk function (K/S), plotted againstthe wavelength λ in nm, for the first exemplary embodiment (AB1) of thephosphor according to the present disclosure. In this case, K/S wascalculated as follows:K/S=(1−R_(inf))²/2R_(inf),wherein R_(inf) corresponds to the diffuse reflection of the phosphor.

It is evident from FIG. 3 that the maximum of K/S for the firstexemplary embodiment (AB1) of the phosphor according to the presentdisclosure is approximately 360 nm. High K/S values mean a highabsorption in this range. The phosphor can be efficiently excited with aprimary radiation starting from approximately 300 nm to 430 nm or 440nm.

FIG. 4 shows a comparison of the full width at half maximum (FWHM), thepeak wavelength (λ_(peak)), the dominant wavelength (λ_(dom)) and theluminous efficiency (LER) between a first comparative example (VB1:BaMgAl₁₀O₁₇:Eu), a second comparative example (VB2: Sr₅(PO₄)₃Cl:Eu), athird comparative example (VB3: BaMgAl₁₀O₁₇:Eu) and the first exemplaryembodiment of the phosphor according to the present disclosureNaLi₃SiO₄:Eu (AB1). VB1 and VB3 differ in the concentration of Eu. Allphosphors emit radiation in the blue range of the electromagneticspectrum. The peak wavelength of the phosphor according to the presentdisclosure NaLi₃SiO₄:Eu is of somewhat longer wavelength in comparisonwith the comparative examples. As evident, the phosphor according to thepresent disclosure NaLi₃SiO₄:Eu has a significantly smaller full widthat half maximum and/or a higher luminous efficiency (LER) than thecomparison examples. The shift in the peak wavelength to a longerwavelength and the smaller full width at half maximum result in anincrease in the overlap with the eye sensitivity curve. Consequently,the phosphor according to the present disclosure has a very highluminous efficiency that is higher in comparison with the comparativeexamples.

FIGS. 5 and 6 show the emission spectra of VB1, VB2, VB3 and AB1, asdescribed in FIG. 4. In FIG. 5, the wavelength in nanometers is plottedon the x-axis and the emission intensity in percent is plotted on they-axis. In FIG. 6, the wave number in cm⁻¹ is plotted on the x-axis andthe emission intensity in percent is plotted on the y-axis. Thesignificantly smaller full width at half maximum of the phosphoraccording to the present disclosure NaLi₃SiO₄:Eu in comparison with VB1and VB3 (BaMgAl₁₀O₁₇:Eu) becomes evident here. In contrast to AB1,moreover, BaMgAl₁₀O₁₇:Eu phosphors exhibit a low absorption startingfrom a wavelength of 350 nm (cf. FIG. 7). Together with the relativelylarge full width at half maximum, that results in a relatively poorcolor purity of the phosphors VB1 and VB3. Although the known phosphorVB2 exhibits a small full width at half maximum, it has the disadvantagethat it contains chlorine. Many applications are subject to strictconditions as far as the chlorine content is concerned, and so theapplication of this phosphor is limited if only for this reason. Therisk of the release of corrosive HCl during its production is alsodisadvantageous, which increases the costs for the synthesis equipmentand the maintenance measures thereof.

FIG. 7 shows a normalized Kubelka-Munk function (K/S), plotted againstthe wavelength λ in nm, for various phosphors VB1, VB2, VB3 and AB1, asdefined in FIG. 4. The curve with the reference signs VB1, VB2 and VB3represents K/S for known phosphors; the curve with the reference signAB1 represents K/S for the first exemplary embodiment of the phosphoraccording to the present disclosure. It is evident that the phosphoraccording to the present disclosure AB1 has a higher absorption atlonger wavelengths, in particular in the range starting from 360 nm, incomparison with the comparative examples VB1, VB2 and VB3. This isparticularly advantageous since an efficient excitation of the phosphoraccording to the present disclosure with a primary radiation having apeak wavelength in the UV range to blue range of the electromagneticspectrum, in particular in the range of between 300 nm and 460 nm,advantageously between 300 nm and 430 nm or 440 nm, is possible.Therefore, the phosphor according to the present disclosure is able tobe employed particularly well in combination with semiconductor chipswhich have a primary radiation in the range of between 300 nm and 430 nmor 440 nm.

FIG. 8 shows the tetragonal crystal structure of the phosphorNaLi₃SiO₄:Eu in a schematic illustration. The hatched circles representthe Na atoms. The crystal structure corresponds to the crystal structureof NaLi₃SiO₄, as described in B. Nowitzki, R. Hoppe, Neues über Oxidevom Typ A[(TO)_(n)]: NaLi₃SiO₄, NaLi₃GeO₄, NaLi₃TiO₄, [New findingsconcerning oxides of the type A[(TO)_(n)]: NaLi₃SiO₄, NaLi₃GeO₄,NaLi₃TiO₄] Revue de Chimie minérale, 1986, 23, 217-230. The crystalstructure is isotypic with respect to that of CaLiAl₃N₄:Eu, described inP. Pust, A. S. Wochnik, E. Baumann, P. J. Schmidt, D. Wiechert, C.Scheu, W. Schnick, Ca[LiAl₃N₄]:Eu²⁺—A Narrow-Band Red-EmittingNitridolithoaluminate, Chemistry of Materials 2014 26, 3544-3549.

Two X-ray diffraction powder diffractograms using copper K_(α1)radiation are indicated in FIG. 9. The diffraction angles in ° θ2 valuesare indicated on the x-axis, and the intensity is indicated on they-axis. The X-ray diffraction powder diffractogram provided with thereference sign I shows that of the first exemplary embodiment AB1 of thephosphor according to the present disclosure NaLi₃SiO₄:Eu. The X-raydiffraction powder diffractogram provided with the reference sign IIshows the X-ray diffraction powder diffractogram for NaLi₃SiO₄ simulatedfrom the crystal structure of NaLi₃SiO₄ (B. Nowitzki, R. Hoppe, Neuesüber Oxide vom Typ A[(TO)_(n)]: NaLi₃SiO₄, NaLi₃GeO₄, NaLi₃TiO₄ , Revuede Chimie minérale, 1986, 23, 217-230). From the correspondence of thereflections it is evident that the phosphor according to the presentdisclosure NaLi₃SiO₄:Eu crystallizes in the same crystal structure asNaLi₃SiO₄.

A crystallographic evaluation is found in FIG. 10. FIG. 10 shows aRietveld refinement of the X-ray powder diffractogram of the firstexemplary embodiment AB1, that is to say for NaLi₃SiO₄:Eu. For theRietveld refinement, the atomic parameters for NaLi₃SiO₄ (table 7 in B.Nowitzki, R. Hoppe, Revue de Chimie minérale, 1986, 23, 217-230) wereused to show that the crystal structure of NaLi₃SiO₄:Eu corresponds tothat of NaLi₃SiO₄. The upper diagram here illustrates thesuperimposition of the measured reflections with the calculatedreflections for NaLi₃SiO₄. The lower diagram illustrates the differencesbetween the measured and calculated reflections.

FIG. 11 shows crystallographic data of NaLi₃SiO₄.

FIG. 12 shows atomic positions in the structure of NaLi₃SiO₄.

FIG. 13 illustrates the emission spectrum of the second exemplaryembodiment AB2 of the phosphor according to the present disclosurehaving the molecular formula KLi₃SiO₄:Eu²⁺. The wavelength in nanometersis plotted on the x-axis and the emission intensity in percent isplotted on the y-axis. For measuring the emission spectrum, the phosphoraccording to the present disclosure was excited with primary radiationhaving a wavelength of 400 nm. The phosphor exhibits a broadbandemission from approximately 430 nm to approximately 780 nm and thusemits white radiation or the emitted radiation produces a white luminousimpression. The color locus of the phosphor is advantageously near thatof the Planckian radiator at 2700 K. The color locus is at the followingcoordinates CIE-x=0.449 and CIE-y=0.397 in the CIE standard chromaticitydiagram from 1931. The color temperature (CCT) is 2742 K, the luminousefficiency is 290 lm/W, the CRI (color rendering index) is 81, and thecolor rendering index R9 is 21. A conversion LED comprising the phosphoraccording to the present disclosure KLi₃SiO₄:Eu²⁺ is thus suitable inparticular for general lighting.

FIG. 14 shows a normalized Kubelka-Munk function (K/S), plotted againstthe wavelength λ in nm, for the second exemplary embodiment (AB2) of thephosphor according to the present disclosure.

It is evident from FIG. 14 that the maximum of K/S for the secondexemplary embodiment (AB2) of the phosphor according to the presentdisclosure invention is approximately 340 nm. The phosphor can beefficiently excited with a primary radiation starting from approximately300 nm to 430 nm or 440 nm.

FIGS. 15 and 16 show simulated emission spectra of various conversionLEDs which emit white radiation. The primary radiation source used is anInGaN-based semiconductor layer sequence which emits a primary radiationhaving a peak wavelength of 410 nm (FIG. 15) or having a peak wavelengthof 390 nm (FIG. 16). The construction of the conversion LEDs is shown inFIG. 17. As evident, the conversion LEDs according to the presentdisclosure (LED 1 and LED 2) using only one phosphor, the KLi₃SiO₄:Eu²⁺according to the present disclosure, exhibit similar emission spectra tothe comparative examples VLED2 and VLED1 each comprising a green and ared phosphor. The phosphor according to the present disclosure thusadvantageously makes it possible to provide a conversion LED which emitswarm-white light having a color temperature of less than 3500 K,advantageously less than 3000 K, and for this purpose requires only onephosphor, unlike known white-emitting conversion LEDs that require atleast one green and one red phosphor in combination with a blue primaryradiation.

FIG. 17 compares various properties of conversion LEDs comprising thephosphor according to the present disclosure KLi₃SiO₄:Eu²⁺ (LED1, LED2)and the comparative examples (VLED1 and VLED2). In this case, λ_(prim)stands for the wavelength of the primary radiation. The first and secondphosphors are indicated in the third and fourth columns. CIE-x and CIE-yindicate the color coordinates x and y of the radiation in the CIEstandard chromaticity diagram from 1931. CCT/K indicates the correlatedcolor temperature of the overall radiation in kelvins. R9 stands for acolor rendering index known to the person skilled in the art (saturatedred). LER stands for the luminous efficiency (“luminous efficacy”) inlumens per watt. As evident, the conversion LEDs comprising the phosphoraccording to the present disclosure KLi₃SiO₄:Eu²⁺ as sole phosphor havesimilar optical properties to conventional conversion LEDs based on twophosphors. In this case, however, the disadvantages arising from the useof two or more phosphors are eliminated. Firstly, the resulting spectrumis greatly dependent on the used ratio of the phosphors. As a result ofbatch fluctuations in phosphor production, frequent adaptations of theconcentration of the phosphors are necessary as a result, which makesthe production of the conversion LEDs very complicated. The phosphorsadditionally exhibit different emission properties depending ontemperature, the radiance of the primary radiation and the excitationwavelength and additionally exhibit a different degradation behavior,that is to say a different stability with regard to temperature,radiation, moisture or gas influences. The production of phosphormixtures may also be difficult if the phosphors differ greatly in theirphysical properties such as, for example, density, grain size and in thesedimentation behavior. With the use of two phosphors, all these effectslead to fluctuating color locus distributions and color shifts underchanging operating conditions, for example current and/or temperature,in the products. In order conventionally to obtain a high colorrendering index, advantageously with low color temperature, inparticular less than 3500 K or less than 3000 K, red-emitting phosphorsare required. However, all known red-emitting phosphors can only besynthesized by means of complex production methods and are thereforevery much more expensive than known green and yellow phosphors. Bycontrast, the phosphor according to the present disclosure KLi₃SiO₄:Eu²⁺can be produced cost-effectively since the starting materials arecommercially available, stable and moreover very inexpensive. Moreover,the synthesis does not require an inert gas atmosphere and thereforeproves to be comparatively simple.

The use of the phosphor according to the present disclosure in awhite-emitting conversion LED has numerous advantages. It is possible touse a primary radiation which is not perceived or is only scarcelyperceived by the human eye (300 nm to 430 nm or 440 nm). Fluctuations ofthe primary radiations thus do not adversely affect the overallradiation properties. No color adaptation is required since the emissionspectrum is constant. The conversion LEDs can be produced with a highthroughput since color adaptation or complex chip binning is notrequired. No color shifts or other negative effects on the emissionspectrum as a result of selective degradation of only one phosphor orchanges in the primary radiation caused by temperature or forwardcurrent fluctuations occur. Furthermore, the conversion LED does nothave an inherent color, but rather exhibits a white appearance in theswitched-off state. Therefore, the phosphor is also suitable for “remotephosphor” arrangements in which a yellow or orange appearance in theswitched-off state is not desired. A partial conversion of the primaryradiation can also be carried out depending on the application. Since itis possible to excite the phosphor with a primary radiation in the rangeof 300 nm to 430 nm or 440 nm, a contribution of the primary radiation,advantageously in the short-wave blue range of the electromagneticspectrum, to the overall radiation has the effect that objectsilluminated thereby appear whiter, more radiant and therefore moreattractive. By way of example, optical brightening agents in textilescan be excited thereby.

FIG. 18 shows a triclinic crystal structure of the phosphor KLi₃SiO₄:Euin a schematic illustration. The hatched circles represent the K atoms.The crystal structure corresponds to the crystal structure of KLi₃SiO₄,as described in K. Werthmann, R. Hoppe, Über Oxide des neuen FormeltypsA[(T₄O₄)]: Zur Kenntnis von KLi₃GeO₄, KLi₃SiO₄ und KLi₃TiO₄ [Regardingoxides of the new formula type A[(T₄O₄)]: Zur Kenntnis von KLi₃GeO₄,KLi₃SiO₄ and KLi₃TiO₄], Z. Anorg. Allg. Chem., 1984, 509, 7-22. Thecrystal structure is isotypic with respect to that of SrLiAl₃N₄:Eu,described in P. Pust, V. Weiler, C. Hecht, A. Tücks, A. S. Wochnik,A.-K. Henß, D. Wiechert, C. Scheu, P. J. Schmidt, W. Schnick,Narrow-Band Red-Emitting Sr[LiAl₃N₄]:Eu²⁺ as a Next-GenerationLED-Phosphor Material Nat. Mater. 2014 13, 891-896.

Two X-ray diffraction powder diffractograms using copper K_(α1)radiation are indicated in FIG. 19. The diffraction angles in ° θ2values are indicated on the x-axis and the intensity is indicated on they-axis. The X-ray diffraction powder diffractogram provided with thereference sign III shows that of the second exemplary embodiment of thephosphor according to the present disclosure KLi₃SiO₄:Eu. The X-raydiffraction powder diffractogram provided with the reference sign IVshows the X-ray diffraction powder diffractogram for KLi₃SiO₄ simulatedfrom the crystal structure of KLi₃SiO₄. From the correspondence of thereflections it is evident that the phosphor according to the presentdisclosure KLi₃SiO₄:Eu crystallizes in the same crystal structure asKLi₃SiO₄.

A crystallographic evaluation is found in FIG. 20. FIG. 20 shows aRietveld refinement of the X-ray powder diffractogram of the secondexemplary embodiment AB2, that is to say KLi₃SiO₄:Eu. For the Rietveldrefinement, the atomic parameters for KLi₃SiO₄ (K. Werthmann, R. Hoppe,Über Oxide des neuen Formeltyps A[(T4O4)]: Zur Kenntnis von KLi3GeO4,KLi3SiO₄ und KLi3TiO4, Z. Anorg. Allg. Chem., 1984, 509, 7-22) are usedto show that the crystal structure of KLi₃SiO₄:Eu corresponds to that ofKLi₃SiO₄. In this case, the upper diagram illustrates thesuperimposition of the measured reflections with the calculatedreflections for KLi₃SiO₄. The lower diagram illustrates the differencesbetween the measured and calculated reflections. A peak of an unknownsecondary phase has been marked with an asterisk.

FIG. 21 shows crystallographic data of KLi₃SiO₄.

FIG. 22 shows atomic positions in the structure of KLi₃SiO₄.

FIG. 23 illustrates the emission spectrum of the third exemplaryembodiment AB3 of the phosphor according to the present disclosurehaving the molecular formula (Na_(0.5)K_(0.5))Li₃SiO₄:Eu²⁺. Thewavelength in nanometers is plotted on the x-axis and the emissionintensity in percent is plotted on the y-axis. For measuring theemission spectrum, the phosphor according to the present disclosure wasexcited with primary radiation having a wavelength of 400 nm. Thephosphor has a full width at half maximum of less than 20 nm and a peakwavelength of 486 nm. With this small full width at half maximum, thisphosphor belongs to the most narrowband Eu²⁺-doped phosphors known. Thepeak wavelength is in the blue-green spectral range of theelectromagnetic spectrum, which spectral range can also be referred toas cyan-colored. Only a small number of phosphors having a peakwavelength in this range have been known hitherto and none of thesephosphors has such a small full width at half maximum. With a peakwavelength of 486 nm and the small full width at half maximum, thephosphor has a good overlap with the eye sensitivity curve. Theconversion of the UV or blue primary radiation into a secondaryradiation having a somewhat longer wavelength in the blue range of theelectromagnetic spectrum (peak wavelength of 486 nm), increases theefficiency of the conversion LED. The peak wavelength of the secondaryradiation is closer to the eye sensitivity maximum at 555 nm incomparison with the primary radiation, whereby the emitted radiation hasa higher overlap with the eye sensitivity curve and is thus perceived asbrighter. Similar optical properties are also obtained with AB9, AB14,AB15 and AB16.

FIG. 24 shows a normalized Kubelka-Munk function (K/S), plotted againstthe wavelength λ in nm, for the third exemplary embodiment (AB3) of thephosphor according to the present disclosure.

It is evident from FIG. 24 that the maximum of K/S for the thirdexemplary embodiment (AB3) of the phosphor according to the presentdisclosure is between 350 nm and 420 nm. Up to 500 nm, K/S issignificantly above the value zero. The phosphor(Na_(0.5)K_(0.5))Li₃SiO₄:Eu²⁺ can be efficiently excited with a primaryradiation starting from approximately 340 nm.

FIG. 25 shows the tetragonal crystal structure of the phosphor(Na_(0.5)K_(0.5))Li₃SiO₄:Eu²⁺ in a schematic illustration. The hatchedcircles represent the Na atoms; the circles enclosing white areasrepresent the K atoms. The crystal structure was determined from X-raypowder diffractogram data. The crystal structure of CsKNa₂Li₁₂Si₄O₁₆with Cs being substituted by K was used as the starting point.

A crystallographic evaluation is found in FIG. 26. FIG. 26 shows aRietveld refinement of the X-ray powder diffractogram of the thirdexemplary embodiment AB3, that is to say (Na_(0.5)K_(0.5))Li₃SiO₄:Eu²⁺.The parameters and atomic coordinates of all non-Li atoms were freelyrefined. In this case, the upper diagram illustrates the superimpositionof the measured reflections with the calculated reflections forCsKNa₂Li₁₂Si₄O₁₆. The lower diagram illustrates the differences betweenthe measured and calculated reflections. The phosphor (Na_(0.5)K_(0.5))Li₃SiO₄:Eu²⁺ is structurally isotypic with respect to the compoundsCsKNa₂Li₈{Li[SiO₄]}4, RbNa₃Li₈{Li[SiO₄]}₄, CsNa₃Li₈{Li[GeO₄]}₄ andRbNa₃Li₈{Li[TiO₄]}4. The structure is also similar to that of the firstexemplary embodiment NaLi₃SiO₄:Eu and the second exemplary embodimentKLi₃SiO₄:Eu of the phosphor according to the present disclosure, but hasa complicated arrangement of the alkali metals.

FIG. 27 shows crystallographic data of (Na_(0.5)K_(0.5))Li₃SiO₄.

FIG. 28 shows atomic positions in the structure of(Na_(0.5)K_(0.5))Li₃SiO₄.

FIG. 29 shows the emission spectra of the third exemplary embodiment ofthe phosphor according to the present disclosure AB3 and threecomparative examples ClS, OS and G, wherein ClS stands forCa₈Mg(SiO₄)₄Cl₂:Eu, OS stands for (Sr,Ba)₂SiO₄:Eu and G stands forLu₃(Al,Ga)₅O₁₂:Ce. All the phosphors emit in the blue to blue-greenrange of the electromagnetic spectrum. AB3, as evident, has the smallestfull width at half maximum and the peak wavelength is shifted to shorterwavelengths in comparison with the comparative examples. Therefore, thephosphor according to the present disclosure is suitable for example foran application in signal lights such as blue lights of, for example,police vehicles, ambulances, emergency doctor vehicles or firedepartment vehicles, the dominant wavelength of which is advantageouslyin a range of between 465 nm and 480 nm. The use of the comparativeexamples is less well suited thereto since the peak wavelengths thereofare above 510 nm, whereas the phosphor according to the presentdisclosure has a peak wavelength of 486 nm. On account of similaroptical properties, AB9, AB14, AB15 and AB16 are also suitable for anapplication in signal lights.

The curve designated by smel shows the sensitivity curve for melatoninproduction, that is to say with what wavelengths melatonin production inthe body can best be suppressed (“human response function for melanopiceffects”; Lucas et al., Trends in Neurosciences January 2014 Vol. 37 No.1). As evident, the emission spectrum of AB3 exhibits a high overlapwith smel, and so this radiation can be effectively used for suppressingthe formation of melatonin. Such irradiation can lead to an increasedvigilance or ability to concentrate.

FIG. 30 shows the overlap of emission spectra of various phosphors (AB3,CIS, OS and G, as described under FIG. 29) and various blue-emittingLEDs (unconverted) with the sensitivity curve for melatonin production.The LEDs are light-emitting diodes having InGaN-based semiconductorchips. The LEDs Ipeak430 nm (peak wavelength of 430 nm) and Ipeak435 nm(peak wavelength of 435 nm) are not usually commercially available inlarge numbers, but are very efficient. The LEDs Ipeak440 nm (peakwavelength of 440 nm), Ipeak445 nm (peak wavelength of 445 nm), Ipeak450nm (peak wavelength of 450 nm) and Ipeak455 nm (peak wavelength of 455nm) are commercially available, inexpensive and efficient. The LEDsIpeak460 nm (peak wavelength of 460 nm), Ipeak465 nm (peak wavelength of465 nm) and Ipeak470 nm (peak wavelength of 470 nm) have only lowefficiency and are not usually commercially available. InGaN-basedsemiconductor chips can in principle emit a radiation having a peakwavelength of up to 500 nm, although the efficiency decreases as thewavelength increases, for which reason they are produced in largenumbers usually only up to a peak wavelength of up to approximately 460nm. As a result, the areas of application for InGaN-based semiconductorchips in light-emitting diodes (without phosphor) are limited. Asevident, the emission of the phosphor according to the presentdisclosure AB3 exhibits a greater overlap with the sensitivity curve formelatonin production than the phosphors ClS, OS and G and also than theInGaN-based LEDs. Melatonin production can thus be efficientlysuppressed with the phosphor according to the present disclosure. Onaccount of similar optical properties, AB9, AB14, AB15 and AB16 are alsosuitable for suppressing melatonin production.

FIG. 31 shows the CIE standard diagram (1931), wherein the CIE-x portionof the primary color red is plotted on the x-axis and the CIE-y portionof the primary color green is plotted on the y-axis. The color loci ofvarious phosphors (AB3, ClS, OS and G, as described under FIG. 29) aredepicted in the CIE standard diagram. The black quadrilaterals representcolor loci of various blue and blue-green InGaN semiconductor chipshaving peak wavelengths of between 430 nm and 492 nm and dominantwavelengths of between 436 nm and 493 nm. The black dot marks the whitepoint Ew having the coordinates CIE-x=1/3 and CIE-y=1/3. The black lineslinking the color loci of a blue indium gallium nitride semiconductorchip (λpeak=445 nm; λdom=449 nm) with the color loci of the phosphorsrepresent the conversion lines of conversion LEDs that are constructedfrom the indium gallium nitride semiconductor chip and correspondingphosphors. The area identified by EVL shows the typical blue color spacefor products for application in the field of signal lights for policevehicles, for example. The open circles mark color loci having 100%color purity for selected dominant wavelengths at 468 nm, 476 nm and 487nm. The dashed line represents color loci having dominant wavelengths at487 nm with varying color purity. Color loci on this dashed line whichlie nearer to the open circle 487 exhibit higher color purities thancolor loci that lie nearer to the white point E. The advantageouseffects of the new phosphor AB3 become clear from this figure: theconversion line (KL) of a typical blue LED to the color locus of thephosphor according to the present disclosure AB3 intersects the EVLcolor space in the center, whereas the conversion lines of the same blueLED comprising the phosphors OS, ClS and G exhibit only a small overlapwith the EVL color space. It is thus advantageously possible to obtain aplurality of color spaces within the EVL color space by using thephosphor AB3 by comparison with the conventional phosphors. Moreover,the conversion line K intersects the dashed line for the dominantwavelength 487 nm at the point I1, which has a higher color purity incomparison with the intersection points of the conversion lines of theknown phosphors. The same improvement in the color purity using thephosphor according to the present disclosure AB3 is also manifested forother target dominant wavelengths, in particular within the EVL colorspace. The corresponding lines are not shown, for the sake of clarity. Ahigh color purity results in a more saturated color impression. Thephosphor according to the present disclosure thus makes it possible toobtain additional color loci which have not been able to be achievedhitherto. The phosphor according to the present disclosure(Na_(0.5)K_(0.5))Li₃SiO₄:Eu²⁺ is therefore particularly suitable forconversion LEDs which emit a blue radiation with high color saturation.These conversion LEDs are suitable for use in blue lights or else for“color on demand” applications. On account of similar opticalproperties, AB9, AB14, AB15 and AB16 are also suitable for conversionLEDs which emit a blue radiation with high color saturation.

FIGS. 32, 33 and 34 show a comparison of the achievable color puritiesof different conversion LEDs at various target dominant wavelengths andwavelengths of the primary radiation. In order to carry out thesimulation experiments, a blue semiconductor chip was combined with thedifferent phosphors AB3, ClS, OS and G. Semiconductor chips based onInGaN and having a high efficiency were used in this case. The contentof phosphor was varied for each experiment in order to attain the targetdominant wavelength; the color purity was subsequently determined fromthe resulting spectra. The results show that for all chosen targetdominant wavelengths and all chosen wavelengths of the primaryradiation, the conversion LEDs comprising the phosphor AB3 and alsocomprising AB9, AB14, AB15 and AB16 (not shown) exhibit a significantlyhigher color purity than the comparative examples.

FIGS. 35, 36 and 37 shows the simulated emission spectra of theconversion LEDs corresponding to FIGS. 32, 33 and 34. In this case, FIG.35 shows the emission spectra of a conversion LED having a primaryradiation of 430 nm and of a conversion LED having a primary radiationof 455 nm in each case comprising the phosphor AB3 at a target dominantwavelength of 468 nm. FIG. 36 shows the emission spectra of a conversionLED having a primary radiation of 430 nm and of a conversion LED havinga primary radiation of 455 nm in each case comprising the phosphor AB3at a target dominant wavelength of 487 nm.

FIG. 37 shows the emission spectra of a conversion LED having a primaryradiation of 430 nm and of a conversion LED having a primary radiationof 455 nm in each case comprising the phosphor AB3 at a target dominantwavelength of 476 nm.

FIG. 38 illustrates the emission spectrum of the fourth exemplaryembodiment AB4 of the phosphor according to the present disclosurehaving the molecular formula (Na_(0.25)K_(0.75))Li₃SiO₄:Eu²⁺. Thewavelength in nm is plotted on the x-axis and the emission intensity in% is plotted on the y-axis. For measuring the emission spectrum, thephosphor according to the present disclosure was excited with a primaryradiation having a wavelength of 400 nm. The phosphor has a full widthat half maximum of less than 50 nm, a peak wavelength of 529 nm, adominant wavelength of 541 nm and a color locus in the CIE color spacehaving the coordinates CIE-x: 0.255 and CIE-y: 0.680. The narrow fullwidth at half maximum of the phosphor leads to a saturated greenemission of the phosphor.

FIG. 39 shows a normalized Kubelka-Munk function (K/S), plotted againstthe wavelength λ in nm, for the fourth exemplary embodiment (AB4) of thephosphor according to the present disclosure. The phosphor according tothe present disclosure can be efficiently excited with a primaryradiation in the range of between 330 nm and 500 nm, advantageously 340nm to 460 nm, particularly advantageously 350 nm to 450 nm. As a result,the phosphor is suitable in particular for backlighting applications,using a semiconductor chip with a primary radiation in the near UV rangeor blue range of the electromagnetic spectrum.

FIG. 40 shows the X-ray powder diffractogram of the fourth exemplaryembodiment AB4. The intensity is indicated on the y-axis and the ° 20values are indicated on the x-axis. The reflection positions and therelative intensity in % of the reflection positions of the X-ray powderdiffractogram are indicated in FIG. 41.

In FIG. 42, the emission intensity in % is plotted against thetemperature in ° C. As evident, the exemplary embodiment AB4 of thephosphor according to the present disclosure exhibits a high thermalstability. FIG. 42 shows the thermal quenching behavior of the phosphoraccording to the present disclosure AB4 in comparison with aconventional phosphor OS2, a green orthosilicate of the formula(Sr,Ba)₂SiO₄:Eu. The phosphors were excited with a blue primaryradiation having a wavelength of 460 nm at various temperatures from 25to 225° C. and their emission intensity was recorded in the process. Itis clearly evident that the phosphor AB4 according to the presentdisclosure has a significantly smaller loss of emission intensity attypical temperatures that prevail in a conversion LED, in particulartemperatures above 140° C. The phosphor can thus advantageously be usedeven at higher operating temperatures in conversion LEDs.

FIG. 43 shows various optical properties of the fourth exemplaryembodiment of the phosphor according to the present disclosure AB4 incomparison with conventional phosphors G2 and OS2. In this case, OS2stands for a phosphor of the formula (Sr,Ba)₂SiO₄:Eu and G2 stands for aphosphor of the formula Lu₃(Al,Ga)₅O₁₂:Ce. All three phosphors exhibit asimilar dominant wavelength. In this case, however, the phosphor AB4according to the present disclosure exhibits a significantly higherluminous efficiency (LER) and a significantly higher color purity. Thisleads to an improved color saturation, as a result of which it ispossible to achieve a higher color space coverage, and to an improvedoverall efficiency. The reason for the improved properties is the smallfull width at half maximum of the fourth exemplary embodiment AB4 havingthe formula (Na_(0.25)K_(0.75))Li₃SiO₄:Eu²⁺ of the phosphor according tothe present disclosure in comparison with the conventional phosphors. Onaccount of a similar position of the peak wavelengths and values of thefull width at half maximum, the exemplary embodiments AB5, AB7, AB13 andAB8 likewise exhibit improved properties. The high luminous efficiencyincreases the efficiency of green conversion LEDs having partial or fullconversion in comparison with green conversion LEDs comprising knowngreen phosphors having a comparable dominant and/or peak wavelength.

FIG. 44 shows a comparison of the emission spectra of the fourthexemplary embodiment AB4 of the phosphor according to the presentdisclosure in comparison with the conventional phosphors G2 and OS2described under FIG. 43.

FIG. 45 shows the coverage of the color space rec2020 (xy) in the CIEcolor space system and rec2020 (u′v′) in the CIE LUV color space system(1976) by different combinations of a green phosphor and a red phosphorin conjunction with a blue primary radiation of varying dominantwavelength. In this case AB4 stands for the fourth exemplary embodiment(Na_(0.25)K_(0.75))Li₃SiO₄:Eu²⁺ of the phosphor according to the presentdisclosure and AB5 stands for the fifth exemplary embodiment(Rb_(0.5)Li_(0.5))Li₃SiO₄ of the phosphor according to the presentdisclosure, and BS stands for a conventional green-emittingbeta-SiAlON:Eu phosphor. The proportions of blue, green and redradiation were adapted such that the white color locus for typicalbacklighting applications (CIE-x=0.278 and CIE-y=0.255) was obtained.Typical color filter curves were applied to the resulting spectrum andthe resulting color loci for blue, green and red were calculated. Theoverlap of the resulting color space with the standard color spaces wasthen calculated and compared. In all cases it is evident that thespectra obtained with the exemplary embodiments AB4 and AB5 of thephosphor according to the present disclosure result in a greatercoverage of the respective color space. Like AB4 and AB5, AB7, AB13 andAB8 also have a high coverage of the respective color space on accountof the similar peak wavelength and full width at half maximum (FIGS. 76,129, 86) in combination with the red phosphors indicated in FIG. 45. Agreater bandwidth of colors can thus be rendered with the phosphorsaccording to the present disclosure. Thus, by way of example, a displaydevice, such as a display, having a conversion LED comprising thephosphor according to the present disclosure can render a significantlyincreased number of colors by comparison with what has been possiblehitherto with conventional phosphors.

FIGS. 46 to 53 show a graphical representation of the results of thecolor space coverage as described in FIG. 45 for a dominant wavelengthof the primary radiation at 448 nm. The second red phosphor used,together with its molecular formula, is indicated in each of thediagrams.

FIGS. 54A, 54B and 54C show a more comprehensive list of the data fromFIG. 45, which additionally show the color loci of the filtered spectraand coverages with other standard color spaces.

FIGS. 55 to 58 show the spanned color spaces of various examples of thecombinations illustrated in FIG. 45 with a wavelength of the primaryradiation λdom=448 nm. Each FIG. shows a comparison of three differentgreen phosphors (AB4, AB5 or BS) in each case combined with a redphosphor, which is indicated with its molecular formula in the figures.The color spaces spanned by the filtered spectra with the exemplaryembodiments according to the present disclosure AB4 and AB5 are almostcongruent. It is evident that a greater bandwidth of colors can berendered with the exemplary embodiments AB4 and AB5 of the phosphoraccording to the present disclosure, primarily in the green and redcorners of the spanned color triangle (marked by arrows). A similarbehavior is also obtained with the exemplary embodiments AB7, AB13 andAB8 (not illustrated). This is assigned to the very narrowband emissionof the phosphors according to the present disclosure AB4 and AB5, AB7,AB13 and AB8. The bandwidth of green colors is thus increased by the useof the phosphors according to the present disclosure AB4, AB5, AB7, AB13and AB8 in comparison with conventional phosphors. The narrow full widthat half maximum of the phosphors according to the present disclosureadditionally reduces the radiation loss that arises as a result of thefiltering. In comparison with the known phosphor β-SiAlON (BS), thephosphors according to the present disclosure can be produced on thebasis of inexpensive starting materials and moreover the synthesis iscarried out at moderate temperatures. This keeps the production costslow, which makes the phosphors also economically highly attractive forthe production of mass-produced products such as LCD televisions,computer monitors or displays for smartphones or tablets.

FIGS. 59 to 62 show the corresponding conversion LED spectra of theexamples of FIGS. 55 to 58. The red phosphor is indicated together withits molecular formula in the figures.

FIG. 63 illustrates the emission spectrum of the fifth exemplaryembodiment AB5 of the phosphor according to the present disclosurehaving the molecular formula (Rb_(0.5)Li_(0.5))Li₃SiO₄. The wavelengthin nm is plotted on the x-axis and the emission intensity in % isplotted on the y-axis. For measuring the emission spectrum, the phosphoraccording to the present disclosure was excited with light having awavelength of 400 nm. The phosphor has a full width at half maximum of43 nm and a peak wavelength of 528 mm and a dominant wavelength of 539nm. The coordinates CIE-x and CIE-y are at 0.238 and 0.694. The phosphorthus proves to be very suitable for backlighting applications that haveto have a saturated green hue.

FIG. 64 shows a standardized Kubelka-Munk function (K/S), plottedagainst the wavelength λ in nm, for the fifth exemplary embodiment ofthe phosphor according to the present disclosure. The maximum of K/S forthe fifth exemplary embodiment of the phosphor according to the presentdisclosure is approximately 400 nm, although the range of highabsorption extends into the blue-green spectral range up toapproximately 500 nm. Therefore, the phosphor can be efficiently excitedwith a primary radiation having a wavelength of between 330 and 500 nm,advantageously 340 and 460 nm, particularly advantageously 350 to 450nm.

FIG. 65 shows the X-ray powder diffractogram of the fifth exemplaryembodiment AB5 of the phosphor according to the present disclosure withthe reference sign V. The X-ray powder diffractogram provided with thereference sign VI shows a simulated diffractogram of the compoundRbLi(Li₃SiO₄)₂ (K. Bernet, R. Hoppe, Ein “Lithosilicat” mitKolumnareinheiten: RbLi₅{Li[SiO₄]}₂ [A “lithosilicate” having columnarunits: RbLi₅{Li[SiO₄]}₂], Z. Anorg. Allg. Chem., 1991, 592, 93-105).Peaks in the X-ray powder diffractogram V which can be assigned to thesecondary phase Li₄SiO₄ are identified by asterisks.

FIG. 66 shows various optical properties of the fifth exemplaryembodiment of the phosphor according to the present disclosure AB5 incomparison with conventional phosphors G1 and OS1. In this case, OS1stands for a phosphor of the formula (Sr,Ba)₂SiO₄:Eu and G1 stands for aphosphor of the formula Lu₃(Al,Ga)₅O₁₂:Ce. In comparison with thephosphors G2 and OS2, the phosphors G1 and OS1 have a different Eu andCe content, respectively, in order in each case to obtain the samedominant wavelength as the exemplary embodiment AB5. All three phosphorsexhibit a similar dominant wavelength. In this case, however, thephosphor according to the present disclosure AB5 exhibits asignificantly higher luminous efficiency (LER) and a significantlyhigher color purity. This leads to an improved color saturation, wherebya higher color space coverage can be achieved, and to an improvedoverall efficiency. The reason for the improved properties is the fullwidth at half maximum of the fourth exemplary embodiment AB5 having theformula (Rb_(0.5)Li_(0.5))Li₃SiO₄ of the phosphor according to thepresent disclosure in comparison with the conventional phosphors. Thehigh luminous efficiency increases the efficiency of green conversionLEDs having partial or full conversion in comparison with greenconversion LEDs comprising known green phosphors having a comparablepeak wavelength.

FIG. 67 shows a comparison of the emission spectra of the fifthexemplary embodiment AB5 of the phosphor according to the presentdisclosure in comparison with the conventional phosphors G1 and OS1described under FIG. 66.

FIG. 68 illustrates the emission spectrum of the first exemplaryembodiment AB1 having the molecular formula NaLi₃SiO₄:Eu and of thesixth exemplary embodiment AB6 having the molecular formulaNa_(0.97)Ca_(0.03)Li_(2.94)Al_(0.09)Si_(0.97)O_(3.88)N_(0.12):Eu. Thewavelength in nanometers is plotted on the x-axis and the emissionintensity in percent is plotted on the y-axis. For measuring theemission spectrum, the phosphors according to the present disclosurewere excited with primary radiation having a wavelength of 400 nm (AB1)and 460 nm (AB6). The phosphor AB1 has a full width at half maximum of32 nm or 1477 cm⁻¹ and a dominant wavelength of 473 nm; the peakwavelength is approximately 469 nm. The phosphor AB6 has a full width athalf maximum of 72.8 nm, a dominant wavelength of 548 nm; the peakwavelength is approximately 516.9 nm. The color locus of AB6 is at thefollowing coordinates CIE-x=0.301 and CIE-y=0.282 in the CIE standardchromaticity diagram from 1931. The luminous efficiency of AB6 is 432.8lm/W. The different properties of AB1 and AB6, in particular the peakwavelength ofNa_(0.97)Ca_(0.03)Li_(2.94)Al_(0.09)Si_(0.97)O_(3.88)N_(0.12):Eu shiftedinto the longer-wavelength range in comparison with NaLi₃SiO₄:Eu, aredue to a greater nephelauxetic effect of the nitrogen atoms surroundingthe activator ions, here the Eu²⁺ ions, in the mixed phaseNa_(0.97)Ca_(0.03)Li_(2.94)Al_(0.09)Si_(0.97)O_(3.88)N_(0.12):Eu. Thehigher the proportion of nitrogen in the vicinity of the activator ions,the longer the peak wavelength. As a result, with an increasing nitrogencontent and thus with a rising value for y* in the phosphorNa_(1−y*)Ca_(y*)Li_(3−2y*)Al_(3y*)Si_(1−y)O_(4−4y*)N_(4y*):Eu, the peakwavelength can be shifted within the visible range of theelectromagnetic spectrum, in particular in a range of between 470 nm and670 nm. The phosphor is thus suitable in particular for lighting devicesor conversion LEDs in which phosphors having very specific propertiesare required (so-called “color on demand” applications).

FIG. 69 shows the emission spectra of AB6 (excitation wavelength 460 nm)and four garnet phosphors as comparative examples (excitation wavelengthin each case 460 nm; 440 nm in the case of Y₃Al₃Ga₂O₁₂:Ce). Incomparison with the known garnet phosphors Y₃Al₅O₁₂:Ce, Y₃Al₃Ga₂O₁₂:Ceand Lu₃Al₅O₁₂:Ce, the exemplary embodiment according to the presentdisclosure AB6 has a peak wavelength shifted to shorter wavelengths anda smaller full width at half maximum. A similar peak wavelength to AB6is exhibited by Lu₃Al₃Ga₂O₁₂:Ce. In comparison with the garnet phosphorsY₃Al₅O₁₂:Ce, Y₃Al₃Ga₂O₁₂:Ce and Lu₃Al₅O₁₂:Ce, the peak wavelength of AB6and Lu₃Al₃Ga₂O₁₂:Ce lies nearer to the blue spectral range, in which inconventional conversion LEDs a spectral gap may disadvantageously befound, in which no or only very little light is emitted. Said spectralgap results in poor color rendering. Therefore, Lu₃Al₃Ga₂O₁₂:Ce is oftenused to reduce the spectral gap. In comparison with Lu₃Al₃Ga₂O₁₂:Ce,however, the sixth exemplary embodimentNa_(0.97)Ca_(0.03)Li_(2.94)Al_(0.09)Si_(0.97)O_(3.88)N_(0.12):Eu has asignificantly smaller full width at half maximum and, owing to thesmaller full width at half maximum, a greater color purity. Anadditional factor is that the exemplary embodiment according to thepresent disclosure AB6 has a higher overlap with the eye sensitivitycurve, thus resulting in a higher luminous efficiency. A comparison ofthe optical data is shown in FIG. 70. The percentages indicated betweenparentheses reflect the changes in the values in comparison withLu₃Al₃Ga₂O₁₂:Ce. The conversion of the UV or blue primary radiation intoa secondary radiation having a wavelength in the green range of theelectromagnetic spectrum (peak wavelength of 516.9 nm) increases theefficiency of a conversion LED. In comparison with the primaryradiation, the peak wavelength of the secondary radiation is nearer tothe eye sensitivity maximum at 555 nm, as a result of which the emittedradiation has a higher overlap with the eye sensitivity curve and isthus perceived as brighter. Conversion LEDs comprising the phosphor inparticular in combination with a green and red phosphor are suitable inparticular for white conversion LEDs, for example for general lighting.In particular, a white overall radiation having a high color temperaturecan be generated.

FIG. 71 shows the tetragonal crystal structure of the phosphorNa_(0.97)Ca_(0.03)Li_(2.94)Al_(0.09)Si_(0.97)O_(3.88)N_(0.12):Eu in aschematic illustration along the crystallographic c-axis. The structurewas determined by X-ray analysis of a single crystal of the phosphor.The hatched circles represent the mixed occupied positions for the Naand Ca atoms. The hatched regions represent the mixed occupiedLi/Si/Al-O/N tetrahedra. The crystal structure corresponds to thecrystal structure of NaLi₃SiO₄:Eu (see FIG. 8). The crystal structure isisotypic with respect to that of CaLiAl₃N₄:Eu, described in P. Pust, A.S. Wochnik, E. Baumann, P. J. Schmidt, D. Wiechert, C. Scheu, W.Schnick, Ca[LiAl₃N₄]:Eu²⁺—A Narrow-Band Red-EmittingNitridolithoaluminate, Chemistry of Materials 2014 26, 3544-3549.

FIG. 72 shows crystallographic data ofNa_(0.97)Ca_(0.03)Li_(2.94)Al_(0.09)Si_(0.97)O_(3.88)N_(0.12):Eu.

FIG. 73 shows atomic positions in the structure ofNa_(0.97)Ca_(0.03)Li_(2.94)Al_(0.09)Si_(0.97)O_(3.88)N_(0.12):Eu.

FIG. 74 illustrates the emission spectrum of the seventh exemplaryembodiment AB7 of the phosphor according to the present disclosurehaving the molecular formula (Na_(0.25)K_(0.5)Li_(0.25)) Li₃SiO₄:Eu²⁺.For measuring the emission spectrum, a single crystal of the phosphoraccording to the present disclosure was excited with a primary radiationhaving a wavelength of 460 nm. The phosphor has a full width at halfmaximum of less than 50 nm, a peak wavelength of 532 nm, a dominantwavelength of 540.3 nm and a color locus in the CIE color space havingthe coordinates CIE-x: 0.235 and CIE-y: 0.640. The narrow full width athalf maximum of the phosphor leads to a saturated green emission of thephosphor. The phosphor (K_(1-r″-r′″)Na_(r″)Li_(r′″))₁(TA)₃(TD)₁(XB)₄:Eor (K_(1-r″-r′″)Na_(r″)Li_(r′″))₁Li₃SiO₄:E where 0<r″<0.5 and 0<r′″<0.5,in particular (Na_(0.25)K_(0.5)Li_(0.25)) Li₃SiO₄:Eu²⁺, is thereforeparticularly attractive for its use in a conversion LED in which anarrowband emission in the green spectral range is required, such as forthe backlighting of LCD displays.

FIG. 75 shows the emission spectra of AB7 and a β-SiAlON:Eu (BS) ascomparative example. The phosphors have comparable peak and dominantwavelengths and color purities, although AB7 exhibits a smaller fullwidth at half maximum and, associated therewith, a greater luminousefficiency and higher color purity. This leads to an improved colorsaturation, as a result of which it is possible to achieve a highercolor space coverage, and to an improved overall efficiency. The reasonfor the improved properties is the small full width at half maximum ofthe seventh exemplary embodiment AB7 having the formula(Na_(0.25)K_(0.50)Li_(0.25))Li₃SiO₄:Eu²⁺ of the phosphor according tothe present disclosure in comparison with the known phosphor BS. Thehigh luminous efficiency increases the efficiency of green conversionLEDs having partial or full conversion in comparison with greenconversion LEDs comprising known green phosphors having a comparabledominant and/or peak wavelength.

The optical data of the phosphors AB7 and BS are shown in FIG. 76. Thephosphor K_(1-r″-r′″)Na_(r″)Li_(r′″))₁(TA)₃(TD)₁(XB)₄:E or(K_(1-r″-r′″)Na_(r″)Li_(r′″))₁Li₃SiO₄:E where 0<r″<0.5 and 0<r′″<0.5, inparticular (Na_(0.25)K_(0.5)Li_(0.25)) Li₃SiO₄:Eu^(2+,) thus proves tobe very suitable for applications in which a saturated green hue isdesired, as in backlighting applications.

FIG. 77 shows the monoclinic crystal structure of the phosphor(Na_(0.25)K_(0.50)Li_(0.25)) Li₃SiO₄:Eu²⁺ in a schematic illustrationalong the crystallographic b-axis. The black circles represent Na atoms,the hatched circles represent K atoms and the circles enclosing whiteareas represent the Li atoms. The phosphor AB7 crystallizes in the samespace group, C2/m, as the fifth exemplary embodiment(Rb_(0.5)Li_(0.5))Li₃SiO₄:Eu²⁺ with comparable lattice parameters. Thecrystal structures of the phosphors (Na_(0.25)K_(0.50)Li_(0.25))Li₃SiO₄:Eu and (Rb_(0.5)Li_(0.5)) Li₃SiO₄:Eu²⁺ have identical (Li₃SiO₄)structural units. The occupation of the channels within these structuralunits is different in this case, however. (Rb_(0.5)Li_(0.5))Li₃SiO₄:Eu²⁺ contains two types of channels, wherein one channel isoccupied only by Rb and the other is occupied only by Li, while(Na_(0.25)K_(0.50)Li_(0.25)) Li₃SiO₄:Eu also contains two types ofchannels, wherein one channel is occupied only by K and the otherchannel is occupied only by Li and Na. The arrangement of Na and K in(Na_(0.25)K_(0.50)Li_(0.25)) Li₃SiO₄:Eu is similar to the arrangement inCsKNaLi(Li₃SiO₄)₄, as described in K. Bernet, R. Hoppe, Z. Anorg. Chem.,1991, 592, 93-105. The exact arrangement of Na and Li within a channelcannot be ascertained by means of X-ray diffraction. A statisticalarrangement is taken as a basis in the present case. The crystalstructure of AB7 is a crystal structure derived from the UCr₄C₄structure type with a higher degree of ordering.

FIG. 78 shows the arrangement of Li, Na and K within the channels of the(Li₃SiO₄) structural units for (Na_(0.25)K_(0.50)Li_(0.25)) Li₃SiO₄:Eu.The black circles represent Na atoms, the hatched circles represent Katoms and the circles enclosing white areas represent the Li atoms. Thearrangement is shown along the crystallographic c-axis.

FIG. 79 shows crystallographic data of (Na_(0.25)K_(0.50)Li_(0.25))Li₃SiO₄:Eu.

FIG. 80 shows atomic positions in the structure of(Na_(0.25)K_(0.50)Li_(0.25)) Li₃SiO₄:Eu.

FIG. 81 shows anisotropic displacement parameters of(Na_(0.25)K_(0.50)Li_(0.25)) Li₃SiO₄:Eu.

FIG. 82 illustrates the emission spectrum of the eighth exemplaryembodiment AB8 of the phosphor according to the present disclosurehaving the molecular formula (Na_(0.5)Rb_(0.5)) Li₃SiO₄:Eu²⁺. Thewavelength in nm is plotted on the x-axis and the emission intensity inpercent is plotted on the y-axis. For measuring the emission spectrum, apowder of the phosphor according to the present disclosure was excitedwith a primary radiation having a wavelength of 400 nm. The phosphor hasa peak wavelength of approximately 525 nm and a dominant wavelength of531 nm. The full width at half maximum is less than 45 nm and the colorlocus in the CIE color space lies at the coordinates CIE-x: 0.211 andCIE-y: 0.671.

FIG. 83 illustrates the emission spectrum of the eighth exemplaryembodiment AB8 of the phosphor according to the present disclosurehaving the molecular formula (Na_(0.5)Rb_(0.5)) Li₃SiO₄:Eu²⁺. Formeasuring the emission spectrum, a powder of the phosphor according tothe present disclosure was excited with a primary radiation having awavelength of 460 nm. The phosphor has a full width at half maximum ofless than 45 nm, a peak wavelength of 528 nm, a dominant wavelength of533 nm and a color locus in the CIE color space having the coordinatesCIE-x: 0.212 and CIE-y: 0.686. The narrow full width at half maximum ofthe phosphor results in a saturated green emission of the phosphor. Onaccount of the small full width at half maximum, the phosphor(Rb_(r*)Na_(1-r*))₁(TA)₃(TD)₁(XB)₄:E or Rb_(r*)Na_(1-r*))₁Li₃SiO₄:Ewhere 0.4≤r*<1.0, in particular (Na_(0.5)Rb_(0.5)) Li₃SiO₄:Eu^(2+,) isparticularly attractive for the use thereof in a conversion LED in whicha narrowband emission in the green spectral range is required, as forthe backlighting of LCD displays.

FIG. 84 shows a normalized Kubelka-Munk function (K/S), plotted againstthe wavelength λ in nm, for the eighth exemplary embodiment (AB8) of thephosphor according to the present disclosure. The phosphor according tothe present disclosure can be efficiency excited with a primaryradiation in the range of between 330 nm and 500 nm, advantageously 340nm to 460 nm, particularly advantageously 350 nm to 450 nm. As a result,the phosphor is suitable in particular for backlighting applications,using a semiconductor chip with a primary radiation in the near UV rangeor blue range of the electromagnetic spectrum.

FIG. 85 shows a comparison of the emission spectra of the eighthexemplary embodiment AB8 of the phosphor according to the presentdisclosure in comparison with the conventional phosphors CIS and OS1described under FIG. 86.

FIG. 86 shows various optical properties of the eighth exemplaryembodiment of the phosphor according to the present disclosure AB8 incomparison with conventional phosphors ClS and OS1. In this case, OS1stands for a phosphor of the formula (Sr,Ba)₂SiO₄:Eu, and ClS stands forCa_(7.8)Eu_(0.2)Mg(SiO₄)₄Cl₂. All three phosphors exhibit a similardominant wavelength. In this case, however, the phosphor AB8 accordingto the present disclosure exhibits a significantly higher luminousefficiency (LER). This leads to an improved color saturation, as aresult of which it is possible to achieve a higher color space coverage,and to an improved overall efficiency. The reason for the improvedproperties is the small full width at half maximum of the eighthexemplary embodiment AB8 having the formula(Na_(0.5)Rb_(0.5))Li₃SiO₄:Eu²⁺ of the phosphor according to the presentdisclosure in comparison with the conventional phosphors. The highluminous efficiency increases the efficiency of green conversion LEDshaving partial or full conversion in comparison with green conversionLEDs comprising known green phosphors having a comparable dominantand/or peak wavelength.

In FIG. 87, the relative brightness in % is plotted against thetemperature in ° C. As is evident, the exemplary embodiment AB8 of thephosphor according to the present disclosure exhibits a high thermalstability. FIG. 87 shows the thermal quenching behavior of the phosphoraccording to the present disclosure AB8 (represented as open squares) incomparison with a conventional phosphor OS1 of the formula(Sr,Ba)₂SiO₄:Eu (represented as filled rhombi). The phosphors wereexcited with a blue primary radiation having a wavelength of 400 nm forthe phosphor according to the present disclosure AB8 and 460 nm for OS1at various temperatures from 25 to 225° C. and their emission intensitywas recorded in the process. It is clearly evident that the phosphoraccording to the present disclosure AB8 has a significantly smaller lossof emission intensity at typical temperatures that prevail in aconversion LED, in particular temperatures above 140° C. The phosphorcan thus advantageously be used even at higher operating temperatures inconversion LEDs. Starting from 125° C., AB8 exhibits a significantlysmaller loss of emission intensity in comparison with OS1. Moreover, AB8at a temperature of 225° C. still exhibits an emission intensity of 90%in comparison with the emission intensity of 100% at 25° C. The emissionintensity at 225° C. is more than twice as high as the emissionintensity of OS1 at 225° C.

FIG. 88 shows the monoclinic crystal structure of the phosphor(Na_(0.5)Rb_(0.5)) Li₃SiO₄:Eu²⁺ in a schematic illustration. The blackcircles represent Rb atoms and the circles enclosing white areasrepresent Na atoms. The phosphor AB8 crystallizes in the same spacegroup, C2/m, as the fifth exemplary embodiment (Rb_(0.5)Li_(0.5))Li₃SiO₄:Eu²⁺ and the sixth exemplary embodiment(Na_(0.25)K_(0.50)Li_(0.25))Li₃SiO₄:Eu with comparable latticeparameters. The crystal structures of the phosphors(Na_(0.5)Rb_(0.5))Li₃SiO₄:Eu²⁺, (Na_(0.25)K_(0.50)Li_(0.25)) Li₃SiO₄:Euand (Rb_(0.5)Li_(0.5)) Li₃SiO₄:Eu²⁺ have the same (Li₃SiO₄) structuralunits. The (Li₃SiO₄) structural units are SiO₄ and LiO₄ tetrahedra,wherein oxygen occupies the corners and Li and Si, respectively, occupythe center of the tetrahedron. The occupation of the channels withinthese structural units is different in this case, however.(Rb_(0.5)Li_(0.5))Li₃SiO₄:Eu²⁺ contains two types of channels, whereinone channel is occupied only by Rb and the other is occupied only by Li,(Na_(0.25)K_(0.50)Li_(0.25)) Li₃SiO₄:Eu also contains two types ofchannels, wherein one channel is occupied only by K and the otherchannel is occupied only by Li and Na, and (Rb_(0.5)Na_(0.s))Li₃SiO₄:Eu²⁺ contains two types of channels, wherein one channel isoccupied only by Rb and the other channel is occupied only by Na.

A crystallographic evaluation is found in FIG. 89. FIG. 89 shows aRietveld refinement of the X-ray powder diffractogram of the eighthexemplary embodiment AB8. The diagram illustrates the superimposition ofthe measured reflections with the calculated reflections for(Na_(0.5)Rb_(0.5)) Li₃SiO₄:Eu, and also the differences between themeasured and calculated reflections. The phosphor is contaminated with asmall proportion of Na₃RbLi₁₂Si₄O₁₆.

FIG. 90 shows crystallographic data of (Na_(0.5)Rb_(0.5))Li₃SiO₄:Eu.

FIG. 91 shows atomic positions in the structure of (Na_(0.5)Rb_(0.5))Li₃SiO₄:Eu.

FIG. 92 illustrates the emission spectrum of the ninth exemplaryembodiment AB9 of the phosphor according to the present disclosurehaving the molecular formula (Rb_(0.25)Na_(0.75)) Li₃SiO₄:Eu. Thewavelength in nm is plotted on the x-axis and the emission intensity in% is plotted on the y-axis. For measuring the emission spectrum, apowder of the phosphor according to the present disclosure was excitedwith a primary radiation having a wavelength of 400 nm. The phosphor hasa peak wavelength of approximately 473 nm and a dominant wavelength of476 nm. The full width at half maximum is at 22 nm and the color locusin the CIE color space is at the coordinates CIE-x: 0.127 and CIE-y:0.120.

FIG. 93 illustrates the emission spectrum of the ninth exemplaryembodiment AB9 of the phosphor according to the present disclosurehaving the molecular formula (Na_(0.75)Rb_(0.25))Li₃SiO₄:Eu²⁺. Formeasuring the emission spectrum, a powder of the phosphor according tothe present disclosure was excited with a primary radiation having awavelength of 420 nm and 440 nm. In comparison with the excitation witha primary radiation of 400 nm as shown in FIG. 92, the phosphor has aneven smaller full width at half maximum of between 19 nm and 21 nm.(Na_(0.75)Rb_(0.25)) Li₃SiO₄:Eu²⁺ and (Na_(0.5)K_(0.5)) Li₃SiO₄:Eu²⁺belong to the most narrowband Eu²⁺-doped phosphors known.

FIG. 94 shows a normalized Kubelka-Munk function (K/S), plotted againstthe wavelength λ in nm, for the ninth exemplary embodiment (AB9) of thephosphor according to the present disclosure, and of BaMgAl₁₀O₁₇:Eu (50mol %) (VB1) as comparative example. The phosphor according to thepresent disclosure can be efficiently excited with a primary radiationin the range of between 340 nm and 470 nm, advantageously 340 nm to 450nm, particularly advantageously 340 nm to 420 nm. As a result, thephosphor (Rb_(r*)Na_(1-r*))₁(TA)₃(TD)₁(XB)₄:E or Rb_(r*)Na_(1-r*))Li₃SiO₄:E where 0<r*<0.4, in particular (Na_(0.75)Rb_(0.25))Li₃SiO₄:Eu^(2+,) is suitable in particular for backlightingapplications, using a semiconductor chip with a primary radiation in thenear UV range or blue range of the electromagnetic spectrum. As isevident, in comparison with VB1, AB9 is able to be efficiently excitedeven in the blue range of the electromagnetic spectrum.

FIG. 95 shows a comparison of the emission spectra of the ninthexemplary embodiment AB9 of the phosphor according to the presentdisclosure in comparison with the conventional phosphors VB1 and VB4described under FIG. 96, at an excitation wavelength of 400 nm.

FIG. 96 shows various optical properties of the ninth exemplaryembodiment of the phosphor according to the present disclosure AB9 incomparison with conventional phosphors VB1 and VB4. In this case, VB1stands for a phosphor of the formula BaMgAl₁₀O₁₇:Eu and VB4 stands for(Ba_(0.75)Sr_(0.25))Si₂O₂N₂:Eu. All three phosphors exhibit a similardominant wavelength and peak wavelength. In this case, however, thephosphor AB9 according to the present disclosure exhibits asignificantly smaller full width at half maximum than the comparativeexamples.

FIG. 97 shows the tetragonal crystal structure of the phosphor(Na_(0.75)Rb_(0.25)) Li₃SiO₄:Eu²⁺ in a schematic illustration. The blackcircles represent Rb atoms and the circles enclosing white areasrepresent Na atoms. The phosphor AB9 crystallizes in the same spacegroup, I4/m, as the third exemplary embodiment(Na_(0.5)K_(0.5))Li₃SiO₄:Eu²⁺. The crystal structures of the phosphors(Na_(0.5)K_(0.5)) Li₃SiO₄:Eu²⁺ and (Na_(0.75)Rb_(0.25)) Li₃SiO₄:Eu²⁺have the same (Li₃SiO₄) structural units. The (Li₃SiO₄) structural unitshave SiO₄ and LiO₄ tetrahedra, wherein oxygen occupies the corners andLi and Si, respectively, occupy the center of the tetrahedron. Theoccupation of the channels within these structural units is different inthe phosphors. (K_(0.5)Na_(0.5)s)Li₃SiO₄:Eu²⁺ contains two types ofchannels, wherein one channel is occupied only by K and the other isoccupied only by Na. (Na_(0.75)Rb_(0.25)) Li₃SiO₄:Eu²⁺ likewise containstwo types of channels, wherein one channel is occupied only by Na andthe other is occupied alternately by Na and Rb in mixed fashion.

A crystallographic evaluation is found in FIG. 98. FIG. 98 shows aRietveld refinement of the X-ray powder diffractogram of the ninthexemplary embodiment AB9. The diagram illustrates the superimposition ofthe measured reflections with the calculated reflections for(Na_(0.75)Rb_(0.25)) Li₃SiO₄:Eu, and also illustrates the differencesbetween the measured and calculated reflections. The phosphor iscontaminated with a small proportion of NaLi₃SiO₄.

FIG. 99 shows crystallographic data of (Na_(0.75)Rb_(0.25))Li₃SiO₄:Eu.

FIG. 100 shows atomic positions in the structure of (Na_(0.75)Rb_(0.25))Li₃SiO₄:Eu.

In FIG. 101, the relative brightness in % is plotted against thetemperature in ° C. As is evident, the exemplary embodiment AB9 of thephosphor according to the present disclosure exhibits a high thermalstability. FIG. 101 shows the thermal quenching behavior of the phosphoraccording to the present disclosure AB9 in comparison with a knownphosphor BaMgAl₁₀O₁₇:Eu (VB1). The phosphors were excited with a blueprimary radiation having a wavelength of 400 nm at various temperaturesfrom 25 to 225° C. and their emission intensity between 410 nm and 780nm was recorded in the process. It is clearly evident that the phosphorAB9 according to the present disclosure has a significantly smaller lossof emission intensity at temperatures above 100° C. At a temperature of225° C., AB9 still exhibits an emission intensity of more than 95% incomparison with the emission intensity of 100% at 25° C.

FIG. 102 illustrates the emission spectrum of the tenth exemplaryembodiment AB10 of the phosphor according to the present disclosurehaving the molecular formula SrSiAl_(0.84)Li_(2.16)O_(1.32)N_(2.68):Eu.For measuring the emission spectrum, a single crystal of the phosphoraccording to the present disclosure was excited with a primary radiationhaving a wavelength of 460 nm. The phosphor has a peak wavelength ofapproximately 628.7 nm and a dominant wavelength of 598 nm. The fullwidth at half maximum is at 99 nm and the color locus in the CIE colorspace is at the coordinates CIE-x: 0.617 and CIE-y: 0.381.

FIG. 103 illustrates the emission spectrum of the tenth exemplaryembodiment AB10 of the phosphor according to the present disclosurehaving the molecular formula SrSiAl_(0.84)Li_(2.16)O_(1.32)N_(2.68):Eu.For measuring the emission spectrum, a powder of the phosphor accordingto the present disclosure was excited with a primary radiation having awavelength of 460 nm. The phosphor has a peak wavelength ofapproximately 632 nm and a dominant wavelength of 600 nm. The full widthat half maximum is at 97.7 nm and the color locus in the CIE color spaceis at the coordinates CIE-x: 0.626 and CIE-y: 0.372. On account ofself-absorption, the emission spectrum of the powder has a smaller fullwidth at half maximum than the emission spectrum of the single crystalfrom FIG. 102.

FIG. 104 shows a normalized Kubelka-Munk function (K/S), plotted againstthe wavelength λ in nm, for the tenth exemplary embodiment (AB10) of thephosphor according to the present disclosure. The phosphor according tothe present disclosure can be efficiency excited with a primaryradiation in the range of between 340 nm and 500 nm, advantageously 340nm to 460 nm.

FIG. 105 illustrates the emission spectrum of the tenth exemplaryembodiment AB10 of the phosphor according to the present disclosurehaving the molecular formula SrSiAl_(0.84)Li_(2.16)O_(1.32)N_(2.68):Euand of two further exemplary embodiments (AB-10a and AB-10b) of thephosphor having the general formulaSr(Si_(0.25)Al_(−1/8+r**/2)Li_(7/8−r**/2))₄ (O_(1−r**)N_(r**))₄. Theexemplary embodiments were produced like AB10; the weighed-in quantitiesare indicated in tables below.

Weighed-in quantities of the starting materials for AB-10a

Starting Substance amount/ material mmol Mass/g NaLi₃SiO₄ 28.08 3.817SrO 26.96 2.794 LiAlH₄ 84.25 3.192 Eu₂O₃ 0.56 0.198

Weighed-in quantities of the starting materials for AB-10b

Starting Substance amount/ material mmol Mass/g NaLi₃SiO₄ 29.82 4.052SrO 22.50 2.331 Li₃N 8.13 0.283 AlN 73.18 3.000 Eu₂O₃ 0.95 0.334

As is evident, by varying r**in the formulaSr(Si_(0.25)Al_(−1/8+r**/2)Li_(7/8−r**/2))₄ (O_(1−r**)N_(r**))₄, it ispossible for the peak wavelength to be shifted from the yellow into thered spectral range. A comparison of optical properties of AB10, AB-10aand AB-10b is shown in FIG. 106. Known phosphors that exhibit emissionsin this spectral range are α-SiAlON:Eu or (Ca,Sr,Ba)₂Si₅N₈:Eu. However,α-SiAlONs exhibit less adjustability of the peak wavelength thanSr(Si_(0.25)Al_(−1/8+r**/2)Li_(7/8−r**/2))₄ (O_(1−r**)N_(r**))₄ and arethus limited in their application. Although a better adjustability ofthe peak wavelength is exhibited by (Ca,Sr,Ba)₂Si₅N₈:Eu, the use thereofis associated with high costs as a result of expensive startingmaterials, such as alkaline earth metal nitrides, and high synthesistemperatures over 1400° C. The phosphor(MB)(Si_(0.25)Al_(−1/8+r**/2)Li_(7/8−r**/2))₄(O_(1−r**)N_(r**))₄:E orSr(Si_(0.25)Al_(−1/8+r**/2)Li_(7/8−r**/2))₄(O_(1-r**)N_(r**))₄:E where0.25≤r**≤1 can thus be adjusted in a targeted manner with regard to thedesired color locus and/or color rendering index depending onrequirements or application. Surprisingly many colors of the visiblerange, in particular from yellow to red, can thus be generated with justone phosphor. The phosphor is suitable in particular for conversionlight-emitting diodes configured to emit a yellow to red radiation or awhite radiation.

FIG. 107 shows the tetragonal crystal structure of the phosphorSrSiAl_(0.84)Li_(2.16)O_(1.32)N_(2.68):Eu in a schematic illustrationalong the crystallographic c-axis. The hatched circles represent Sratoms and hatched regions represent (Li,Si,Al)(O,N)₄ tetrahedra. Thephosphor AB10 crystallizes in the UCr₄C₄ structure type. The Sr atomsare situated in tetragonal channels formed by the corner- andedge-linked (Li,Si,Al)(O,N)₄ tetrahedra. The phosphor crystallizes inthe space group I4/m.

FIG. 108 shows crystallographic data ofSrSiAl_(0.84)Li_(2.16)O_(1.32)N_(2.68):Eu.

FIG. 109 shows atomic positions in the structure ofSrSiAl_(0.84)Li_(2.16)O_(1.32)N_(2.68):Eu.

FIG. 110 shows anisotropic displacement parameters ofSrSiAl_(0.84)Li_(2.16)O_(1.32)N_(2.68):Eu.

FIG. 111 shows a crystallographic evaluation of the X-ray powderdiffractogram of the tenth exemplary embodiment AB10.

The diagram illustrates the superimposition of the measured reflectionswith the calculated reflections forSrSiAl_(0.84)Li_(2.16)O_(1.32)N_(2.68):Eu. The upper part of the diagramshows the experimentally observed reflections (Cu Kai radiation); thelower part of the diagram shows the calculated reflection positions. Thecalculation was made on the basis of the structure model forSrSiAl_(0.84)Li_(2.16)O_(1.32)N_(2.68):Eu, as described in FIGS.107-110. Reflections of secondary phases are identified by *. Thesecondary phases are present in a very small proportion.

FIG. 112 illustrates the emission spectrum of the eleventh exemplaryembodiment AB11 of the phosphor according to the present disclosurehaving the molecular formulaNa_(1−y*)Eu_(y**)Li_(3−2y**)Al_(3y**)*Si_(1−y**)O_(4−4y**)N_(4y**):Euwhere y**=0.2224 in comparison with the first exemplary embodiment AB1NaLi₃SiO₄. The phosphor AB11 has a peak wavelength of approximately613.4 nm and a dominant wavelength of 593.6 nm. The full width at halfmaximum is at 105 nm and the color locus in the CIE color space is atthe coordinates CIE-x: 0.595 and CIE-y: 0.404. The different propertiesof AB1 and AB11, in particular the peak wavelength shifted into thelonger-wavelength range forNa_(1−y**)Eu_(y**)Li_(3−2y**)Al_(3y**)Si_(1−y**)O_(4−4y**)N_(4y**):Euwhere y**=0.2224 in comparison with NaLi₃SiO₄:Eu is due to a strongernephelauxetic effect of the nitrogen atoms surrounding the activatorions, here the Eu²⁺ ions, in the mixed phaseNa_(1−y**)Eu_(y**)Li_(3−2y**)Al_(3y**)Si_(1−y**)O_(4−4y**)N_(4y**):Euwhere y**=0.2224. The higher the proportion of nitrogen in the vicinityof the activator ions, the longer the peak wavelength. As a result, withincreasing nitrogen content and thus with a rising value for y**in thephosphorNa_(1−y**)Eu_(y**)Li_(3−2y**)Al_(3y**)Si_(1−y**)O_(4−4y**)N_(4y**):Eu,the peak wavelength can be shifted within the visible range of theelectromagnetic spectrum, in particular in a range of between 470 nm and670 nm. The phosphor(MA)_(1−y***)Sr_(y***)Li_(3−2y***)Al_(3y***)Si_(1−y***)O_(4−4y***)N_(4y***):Eor Na_(1−y**)Eu_(y**)Li_(3−2y**)Al_(3y**)Si_(1−y**)O_(4−4y**)N_(4y**):Ewhere 0<y***<0.875 is thus suitable in particular for lighting devicesor conversion LEDs in which phosphors having very specific propertiesare required (so-called “color on demand” applications), for example forflashing lights in a motor vehicle.

Optical data for AB11 are shown in FIG. 113.

FIG. 114 shows the tetragonal crystal structure of the phosphorNa_(1−y*)Eu_(y**)Li_(3−2y**)Al_(3y**)Si_(1−y**)O_(4−4y**)N_(4y**):Euwhere y**=0.2224 (AB11) and in a schematic illustration along thecrystallographic c-axis. The hatched circles represent Na/Eu atoms andthe hatched regions represent (Li,Si,Al)(O,N)₄ tetrahedra. The phosphorAB11 crystallizes in the UCr₄C₄ structure type. The Na and Eu atoms aresituated in tetragonal channels formed by the corner- and edge-linked(Li,Si,Al)(O,N)₄ tetrahedra. The phosphor crystallizes in the spacegroup I4/m. The crystal structure is known e.g. for phosphors of theformula Sr[Mg₂Al₂N₄]:Eu²⁺ (WO 2013/175336 A1 or P. Pust et al., Chem.Mater., 2014, 26, 6113). Surprisingly, in the present case it has beenpossible to show that even phosphors having a proportion of less than87.5% nitrogen can be synthesized and are stable.

FIG. 115 shows crystallographic data ofNa_(1−y**)Eu_(y**)Li_(3−2y**)Al_(3y**)Si_(1−y**)O_(4−4y**)N_(4y**):Euwhere y**=0.2224.

FIG. 116 shows atomic positions in the structure ofNa_(1−y**)Eu_(y**)Li_(3−2y**)Al_(3y**)Si_(1−y**)O_(4−4y**)N_(4y**):Euwhere y**=0.2224.

FIG. 117 shows anisotropic displacement parameters ofNa_(1−y**)Eu_(y**)Li_(3−2y**)Al_(3y**)Si_(1−y**)O_(4−4y**)N_(4y**):Euwhere y**=0.2224.

FIG. 118a shows a crystallographic evaluation of the X-ray powderdiffractogram of the eleventh exemplary embodiment AB11. The diagramillustrates a comparison of the measured reflections with the calculatedreflections forNa_(1−y**)Eu_(y**)Li_(3−2y**)Al_(3y**)Si_(1−y**)O_(4−4y**)N_(4y**):Euwhere y**=0.2224. The upper part of the diagram shows the experimentallyobserved reflections (Mo K_(α1) radiation); the lower part of thediagram shows the calculated reflection position. The calculation wasmade on the basis of the structure model forNa_(1−y**)Eu_(y**)Li_(3−2y**)Al_(3y**)Si_(1−y**)O_(4−4y**)N_(4y**):Euwhere y**=0.2224, as described in FIGS. 114-117. The correspondence ofthe reflections of the calculated powder diffractogram to thereflections of the measured powder diffractogram reveals acorrespondence of the crystal structure of single crystals and powdersof the phosphor.

FIG. 118b shows the emission spectra ofNa_(1−y**)Eu_(y**)Li_(3−2y**)Al_(3y**)Si_(1−y**)O_(4−4y**)N_(4y**):Euwhere y**=0.1 (AB11-1),Na_(1−y*)Ca_(y*)Li_(3−2y*)Al_(3y*)Si_(1−y*)O_(4−4y*)N_(4y*):Eu wherey*=0.25 (AB6-1; AB6-2) andNa_(1−y***)Sr_(y***)Li_(3−2y***)Al_(3y***)Si_(1−y***)O_(4−4y***)N_(4y***):Euwhere y***=0.25 (AB18). A comparison of the optical properties is shownin FIG. 119.

FIG. 120 shows an excerpt from the CIE color space. In this excerpt, theregion designated by ECE corresponds to color loci for flashing lightsin the exterior region of a motor vehicle in the yellow or yellow-orangecolor range which correspond to the ECE regulations (ECE: EconomicCommission for Europe). The ECE regulations are a catalog ofinternationally agreed, standardized technical specifications for motorvehicles and for parts and items of equipment of motor vehicles.Furthermore, the color loci of the eleventh exemplary embodiment AB11and of a comparative example (Sr,Ca,Ba)₂Si₅N₈:Eu (Comp 258) are shown.The color loci of both phosphors lie within the ECE region and aretherefore suitable for the use of said phosphors in conversion LEDs forflashing lights in motor vehicles. In contrast to (Sr,Ca,Ba)₂Si₅N₅:Eu,the phosphor according to the present disclosure AB11 can be produced atlower temperatures. A yellow or yellow-orange conversion LED comprisingAB11 (full conversion) is much more efficient and moretemperature-stable in comparison with a yellow or yellow-orange LED,based on InGaAlP.

FIG. 121 shows the color loci of AB11 and Comp 258.

FIG. 122 illustrates the emission spectrum of a single crystal of thetwelfth exemplary embodiment AB12 of the phosphor according to thepresent disclosure having the molecular formulaSrLi_(3−2x**)Al_(1+2x**)O_(4−4x**)N_(4x**):Eu where x**=0.2014 incomparison with a comparative example (Ca,Sr,Ba)₂SiO₄:Eu. The phosphorAB12 has a peak wavelength of approximately 580.3 nm and a dominantwavelength of 576.5 nm. The full width at half maximum is at 80 nm andthe color locus in the CIE color space is at the coordinates CIE-x:0.486 and CIE-y: 0.506. A comparison of the optical data of AB12 and(Ca, Sr,Ba)₂SiO₄:Eu is illustrated in FIG. 123. (MB)Li_(3−2x**)Al_(1+2x**)O_(4−4x**)N_(4x**):Eu orSrLi_(3−2x**)Al_(1+2x**)O_(4−4x**)N_(4x**):Eu where 0<x**<0.875, inparticular where x**=0.2014, is suitable for use in colored conversionLEDs in which the primary radiation is completely or almost completelyconverted into secondary radiation and is thus usable in particular for“color on demand” applications. As illustrated in FIG. 123, a conversionLED comprising AB12 has a higher luminous efficiency than a conversionLED comprising (Ca, Sr,Ba)₂SiO₄:Eu.

FIG. 124 shows simulated emission spectra of conversion LEDs. Emissionspectra of conversion LEDs with a primary radiation of 442 nm with thetwelfth exemplary embodiment AB12 and phosphors as comparative examplesare shown. White emission spectra in which the overall radiation iscomposed of the primary radiation and the respective secondary radiationare shown. The optical data are illustrated in FIG. 125. On account ofthe small full width at half maximum of AB12 in comparison with thecomparative examples, the conversion LED comprising the phosphoraccording to the present disclosure AB12 has a higher luminousefficiency (LER) since the overlap with the eye sensitivity curve isgreater than in the comparative examples. (MB)Li_(3−2x**)Al_(1+2x**)O_(4−4x**)N_(4x**):Eu orSrLi_(3−2x**)Al_(1+2x**)O_(4−4x**)N_(4x**)N:Eu where 0<x**<0.875, inparticular the twelfth exemplary embodiment, is thus suitable inparticular for use as sole phosphor in a conversion LED for generatingwarm-white overall radiation, in particular having a color temperatureof 3400 K±100 K in combination with a primary radiation in the UV toblue range, for example with a layer sequence based on InGaN. Colortemperatures of 3400 K±100 K with color loci near the Planckian locusare not achieved with the use of Y₃Al₅O₁₂:Ce. Although the use ofmodifications of Y₃Al₅O₁₂:Ce, such as (Y,Lu,Gd,Tb)₃(Al,Ga)₅O₁₂:Ce (FIG.125), leads to the desired color loci and color temperatures, theluminous efficiency is lower than with the use of Y₃Al₅O₁₂:Ce and thethermal quenching behavior is higher. Orthosilicates such as(Ca,Sr,Ba)₂SiO₄:Eu are thermally and chemically less stable incomparison with Y₃Al₅O₁₂:Ce and additionally have a poorer luminousefficiency in comparison with a conversion LED comprising AB12.

FIG. 114 and FIG. 160 show the tetragonal crystal structure of thephosphor SrLi_(3−2x**)Al_(1+2x**)O_(4−4x**)N_(4x**):Eu where x**=0.2014(AB12) in a schematic illustration along the crystallographic c-axis.The hatched circles represent Sr atoms and hatched regions represent(Li,Al)(O,N)₄ tetrahedra. The phosphor AB12 crystallizes in the UCr₄C₄structure type. The phosphor crystallizes in the space group I4/m. Thecrystal structure is known e.g. for phosphors of the formulaSr[Mg₂Al₂N₄]:Eu²⁺ (WO 2013/175336 A1 or P. Pust et al., Chem. Mater.,2014, 26, 6113). The (Li,Al)(O,N)₄ tetrahedra form tetragonal channelsin which the Sr atoms are arranged. Surprisingly, in the present case ithas been possible to show that even phosphors having a proportion ofless than 87.5% nitrogen can be synthesized and are stable. Thephosphors of the formula SrLi_(3−2x**)Al_(1+2x**)O_(4−4x**)N_(4x**):Euwhere x**≥0.1250 crystallize in this crystal type, which has been ableto be shown on the basis of the exemplary embodiments AB12-1 to AB12-8.With increasing x**, the volume of the unit cell increases and the peakwavelength is shifted to longer wavelengths.

FIG. 126 shows crystallographic data ofSrLi_(3−2x**)Al_(1+2x**)O_(4−4x**)N_(4x**):Eu where x**=0.2014 (AB12).

FIG. 127 shows atomic positions in the structure ofSrLi_(3−2x**)Al_(1+2x**)O_(4−4x**)N_(4x**):Eu where x**=0.2014 (AB12).

FIG. 128 shows anisotropic displacement parameters ofSrLi_(3−2x**)Al_(1+2x**)O_(4−4x**)N_(4x**):Eu where x**=0.2014 (AB12).

FIG. 129 illustrates the emission spectrum of AB13 of the phosphoraccording to the present disclosure having the molecular formula(Cs_(0.25)Na_(0.25)K_(0.25)Li_(0.25)) Li₃SiO₄:Eu²⁺. For measuring theemission spectrum, a powder of the phosphor according to the presentdisclosure was excited with a primary radiation having a wavelength of400 nm. The phosphor has a full width at half maximum of 46 nm, a peakwavelength of 530 nm and a dominant wavelength of 532 nm. The colorlocus is at CIE-x: 0.222 and CIE-y: 0.647. The optical properties aresimilar to those of the eighth exemplary embodiment. The peak atapproximately 490 nm is probably attributable to a contamination byCsNa₂K(Li₃SiO₄)₄:Eu²⁺. FIG. 130 shows a normalized Kubelka-Munk function(K/S), plotted against the wavelength λ in nm, for AB13. The phosphorcan be efficiently excited with a primary radiation in the blue range.

FIG. 131 illustrates the emission spectrum of AB14 of the phosphoraccording to the present disclosure having the molecular formula(Cs_(0.25)Na_(0.5)K_(0.25))Li₃SiO₄:Eu²⁺. For measuring the emissionspectrum, a powder of the phosphor according to the present disclosurewas excited with a primary radiation having a wavelength of 400 nm. Thephosphor has a full width at half maximum of 26 nm, a peak wavelength of486 nm and a dominant wavelength of 497 nm. The color locus is at CIE-x:0.138 and CIE-y: 0.419.

FIG. 132 shows a normalized Kubelka-Munk function (K/S), plotted againstthe wavelength λ in nm, for AB14. The phosphor can be efficientlyexcited with a primary radiation in the blue range.

FIG. 133 illustrates the emission spectrum of AB15 of the phosphoraccording to the present disclosure having the molecular formula(Rb_(0.25)Na_(0.5)K_(0.25)) Li₃SiO₄:Eu²⁺. For measuring the emissionspectrum, a powder of the phosphor according to the present disclosurewas excited with a primary radiation having a wavelength of 400 nm. Thephosphor has a full width at half maximum of 27 nm, a peak wavelength of480 nm and a dominant wavelength of 490 nm. The color locus is at CIE-x:0.139 and CIE-y: 0.313. The peak at approximately 530 nm is probablyattributable to a contamination by RbNa(Li₃SiO₄)₂ or K₂NaLi(Li₃SiO₄)₄.

FIG. 134 shows a normalized Kubelka-Munk function (K/S), plotted againstthe wavelength λ in nm, for AB15. The phosphor can be efficientlyexcited with a primary radiation in the blue range.

FIG. 135 illustrates the emission spectrum of AB16 of the phosphoraccording to the present disclosure having the molecular formula(Cs_(0.25)Na_(0.25)Rb_(0.25)Li_(0.25)) Li₃SiO₄:Eu²⁺. For measuring theemission spectrum, a powder of the phosphor according to the presentdisclosure was excited with a primary radiation having a wavelength of400 nm. The phosphor has a full width at half maximum of 24 nm, a peakwavelength of 473 nm, and a dominant wavelength of 489 nm. The peak atapproximately 530 nm is probably attributable to a contamination byRbNa(Li₃SiO₄)₂.

The optical properties of AB14, AB15 and AB16 are similar to those ofAB9 and AB3.

FIG. 136 shows a normalized Kubelka-Munk function (K/S), plotted againstthe wavelength λ in nm, for AB16. The phosphor can be efficientlyexcited with a primary radiation in the blue range.

FIG. 137 shows the tetragonal crystal structure of AB13 of the phosphoraccording to the present disclosure having the molecular formula(Cs_(0.25)Na_(0.25)K_(0.25)Li_(0.25)) Li₃SiO₄:Eu²⁺. The black circlesrepresent Cs atoms, the circles enclosing white areas represent Liatoms, the circles with ruled lines represent K atoms and the checkedcircles represent Na atoms. The crystal structure is similar to thecrystal structure of the ninth exemplary embodiment AB9; AB13crystallizes in the same space group, I4/m. The (Li₃SiO₄) structuralunits have SiO₄ and LiO₄ tetrahedra, wherein oxygen occupies the cornersand Li and Si, respectively, occupy the center of the tetrahedron.(Cs_(0.25)Na_(0.25)K_(0.25)Li_(0.25))Li₃SiO₄:Eu²⁺ contains two types ofchannels within the (Li₃SiO₄) structural units, wherein one channel isoccupied by Na and Li and the other is occupied alternately by Cs and K.The arrangement of Na and Li within one channel corresponds to that ofAB7. The exact arrangement of Na and Li within one channel cannot beascertained by means of X-ray diffraction.

FIG. 138 shows the tetragonal crystal structure of AB14 of the phosphoraccording to the present disclosure having the molecular formula(Cs_(0.25)Na_(0.5)K_(0.25))Li₃SiO₄:Eu²⁺. The black circles represent Csatoms, the circles with ruled lines represent K atoms and the checkedcircles represent Na atoms. The crystal structure is similar to thecrystal structure of the ninth exemplary embodiment AB9; AB13crystallizes in the same space group I4/m. The (Li₃SiO₄) structuralunits have SiO₄ and LiO₄ tetrahedra, wherein oxygen occupies the cornersand Li and Si, respectively, occupy the center of the tetrahedron.(Cs_(0.25)Na_(0.5)K_(0.25))Li₃SiO₄:Eu²⁺ contains two types of channelswithin the (Li₃SiO₄) structural units, wherein one channel is occupiedby Na and the other is occupied alternately by Cs and K.

FIG. 139 shows the tetragonal crystal structure of AB15 of the phosphoraccording to the present disclosure having the molecular formula(Rb_(0.25)Na_(0.5)K_(0.25))Li₃SiO₄:Eu²⁺. The black circles represent Rbatoms, the circles with ruled lines represent K atoms and checkedcircles represent Na atoms. The crystal structure is isostructural withrespect to that of AB14, wherein the positions of the Cs atoms areoccupied by Rb atoms.

FIG. 140 shows the tetragonal crystal structure of AB16 of the phosphoraccording to the present disclosure having the molecular formula(Cs_(0.25)Na_(0.25)Rb_(0.25)Li_(0.25)) Li₃SiO₄:Eu²⁺. The black circlesrepresent Cs atoms, the circles with ruled lines represent Rb atoms, thechecked circles represent Na atoms and the white circles represent Liatoms. The crystal structure is isostructural with respect to that ofAB13, wherein the positions of the K atoms are occupied by Rb atoms.

FIGS. 141-144 each show a Rietveld refinement of the X-ray powderdiffractogram of AB13 (FIG. 141), of AB14 (FIG. 142), of AB15 (FIG. 143)and of AB16 (FIG. 144). The diagram illustrates the superimposition ofthe measured reflections with the calculated reflections, and also thedifferences between the measured and calculated reflections.

FIG. 145 shows crystallographic data and FIG. 146 shows atomic positionsof AB13.

FIG. 147 shows crystallographic data and FIG. 148 shows atomic positionsof AB14.

FIG. 149 shows crystallographic data and FIG. 150 shows atomic positionsof AB15.

FIG. 151 shows crystallographic data and FIG. 152a shows atomicpositions of AB16.

FIG. 152b shows the emission spectrum of single crystals of thephosphors AB12-1 and AB12-2 of the phosphor according to the presentdisclosure having the molecular formulaeSrLi_(3−2x**)Al_(1+2x**)O_(4−4x**)N_(4x**):Eu²⁺ where x**=0.125 (AB12-1)and x**=0.1375 (AB12-2). The optical properties are shown in FIG. 153.

FIG. 154 shows the emission spectrum of a single crystal of the phosphorSrLi_(3−2x**)Al_(1+2**)O_(4−4x**)N_(4x**):Eu²⁺ where x**<0.125. Thephosphors SrLi_(3−2x**)Al_(1+2x**)O_(4−4x**)N_(4x**):Eu²⁺ wherex**<0.125 have a smaller full width at half maximum than phosphors wherex**≥0.125. The optical properties are shown in FIG. 155. The crystalstructure of phosphors of the formulaSrLi_(3−2x**)Al_(1+2x**)O_(4−4x**)N_(4x**):Eu²⁺ where x**<0.125 isrelated to the UCr₄C₄ structure type, although reflections in singlecrystal diffraction data indicate a higher degree of ordering. Thisresults in a crystal structure having a higher degree of ordering thatis derived from the UCr₄C₄ structure type. Surprisingly, phosphorshaving a higher oxygen content exhibit a higher degree of orderingwithin the crystal structure. The smaller full width at half maximum isattributable to the higher degree of ordering of the crystal structure.

FIG. 156 illustrates the peak wavelength λpeak in nm plotted against thecell volume of the unit cell of the crystal structure of phosphors ofthe formula SrLi_(3−2x**)Al_(1+2x**)O_(4−4x**)N_(4x**):Eu wherex**≥0.1250 for powders and single crystals ofSrLi_(3−2x**)Al_(1+2x**)O_(4−4x**)N_(4x**):Eu having differentproportions of x**. The differences in the peak wavelengths in themeasurement of powders and single crystals are caused by reabsorptioneffects in the powder measurement, which can lead to a long-wave shiftin the observed peak wavelength. The peak wavelengths can be adjusted byadapting the cell volume of the unit cell. As x**rises, the cell volumeof the unit cell increases and at the same time the peak wavelength isshifted into the longer-wavelength range. Advantageously, by varyingx**≥0.125, it is possible for the peak wavelength to be shifted from thegreen into the red spectral range. The peak wavelengths and cell volumes(V) for various proportions x**are shown in FIG. 157. As a result, thephosphor of the general molecular formulaSrLi_(3−2x**)Al_(1+2x**)O_(4−4x**)N_(4x**):Eu is interesting for verymany applications. In particular, it is possible to provide phosphorswhich have peak wavelengths between those of the yellow-emittingY₃Al₅O₁₂:Ce, of the orange-red-emitting (Ca, Sr,Ba)₂Si₅N₈:Eu and of thered-emitting (Sr,Ca) SiAlN₃:Eu.

FIG. 158 shows crystallographic data of single crystals of the phosphorsAB12-1 and AB12-2 of the phosphor according to the present disclosurehaving the molecular formulaeSrLi_(3−2x**)Al_(1+2x**)O_(4−4x**)N_(4x**):Eu²⁺ where x**=0.125 (AB12-1)and x**=0.1375 (AB12-2).

FIG. 159 shows atomic positions in the structure ofSrLi_(3−2x**)Al_(1+2x**)O_(4−4x**)N_(4x**):Eu²⁺ for AB12-2.

FIG. 161 illustrates the emission spectrum of AB17 of the phosphoraccording to the present disclosure having the molecular formulaNa_(0.125)K_(0.875)Li₃SiO₄:Eu. For measuring the emission spectrum, asingle crystal of the phosphor according to the present disclosure wasexcited with a primary radiation having a wavelength of 460 nm. Thecurves designated by Peak1 and Peak2 represent two Gaussian curves fordescribing the total emission with two emission peaks. The measuredcurve is congruent with the sum of the two Gaussian curves as calculatedcurve. The wavelength of the emission peak having the highest intensityis referred to as peak wavelength. The wavelength of the emission peakhaving lower intensity is referred to as relative emission maximum. Thedata resulting from the spectrum are summarized in FIG. 162.

FIG. 163 shows the emission spectrum of three embodiments of thephosphor according to the present disclosure (Na_(r)K_(1−r))₁Li₃SiO₄:Euwhere 0.05<r<0.2 with different proportions r. These also exhibit a wideemission.

FIG. 164 shows an overview of simulated optical data of conversion LEDs.A blue-emitting semiconductor chip based on InGaN is used as primaryradiation source; the peak wavelength of the primary radiation is 438 nmor 443 nm. The phosphors used for converting the primary radiation areAB17 and (Lu,Y)₃Al₅O₁₂:Ce. The comparative examples are identified byComp1, Comp2 and Comp3 and the embodiments according to the presentdisclosure by AB17-LED1 and AB17-LED2. For all the conversion LEDs, theoverall radiation of the conversion LEDs results from a superimpositionof the primary and secondary radiations. The color loci of the overallradiation all lie in the cold-white range with color temperatures ofmore than 8000 K close to the locus of the Planckian radiator.Surprisingly, the embodiments according to the present disclosure have ahigh color rendering index where CRI>80 and R9>50, while the comparativeexamples only have a CRI<70 and R9<0. This is attributable to the wideemission of the phosphor AB17 from the green to the red spectral range.The phosphor (Na_(r)K_(1−r))₁(TA)₃(TD)₁(XB)₄:Eu where 0.05<r<0.2, inparticular (Na_(r)K_(1−r))₁Li₃SiO₄:Eu, is thus suitable in particularfor conversion LEDs for general lighting. The phosphor canadvantageously be used as sole phosphor in a conversion LED for generallighting.

FIG. 165 illustrates the color loci of the overall radiation of theconversion LEDs from FIG. 164. As is evident, the color loci are allsituated close to the color loci of the Planckian radiator.

FIG. 166 illustrates emission spectra of the conversion LEDs AB17-LED2and Comp2 from FIG. 164.

FIG. 167 shows an overview of simulated optical data of conversion LEDs.A blue-emitting semiconductor chip based on InGaN is used as primaryradiation source; the peak wavelength is 443 nm, 446 nm or 433 nm. Thephosphors used for converting the primary radiation are AB17 andLu₃Al₅O₁₂:Ce. The comparative examples are identified by Comp4 and Comp5and the embodiments according to the present disclosure are identifiedby AB17-LED3, AB17-LED4 and AB17-LED5. In the embodiments according tothe present disclosure, only AB17 is used as phosphor, while in thecomparative examples, a second, red-emitting phosphor CaAlSiN₃:Eu isused alongside Lu₃Al₅O₁₂:Ce. Surprisingly, the overall radiation of theembodiments according to the present disclosure has a very large overlapwith the transmission range of standard filters and filters for largercolor spaces (HCG, High Color Gamut), such that only little light islost and the achievable color space is as large as possible. As isevident, with the embodiments according to the present disclosure havingonly one phosphor, it is possible to obtain a high, in some instancesgreater coverage of the colors of the sRBG color space than with thecomparative examples in which two phosphors are used. The phosphor(Na_(r)K_(1−r))₁(TA)₃(TD)₁(XB)₄:Eu where 0.05<r≤0.2, in particular(Na_(r)K_(1−r))₁Li₃SiO₄:Eu, is thus suitable in particular forconversion LEDs for backlighting applications. The phosphor canadvantageously be used as sole phosphor in a conversion LED forbacklighting applications.

FIG. 168 illustrates emission spectra of the conversion LEDs AB17-LED5and Comp5 from FIG. 167.

FIGS. 169 and 170 show the spanned color spaces of the filtered overallradiation of various conversion LEDs from FIG. 167 and the overlapthereof with the sRGB color space. It is evident that a large bandwidthof colors can be rendered with the exemplary embodiments AB17-LED3 andAB17-LED5; primarily in the green corner of the spanned color triangleit is possible to attain more colors than with the exemplaryembodiments.

FIG. 171 shows a unit cell of the tetragonal crystal structure of thephosphor Na_(0.125)K_(0.875)Li₃SiO₄:Eu (AB17) in a schematicillustration along the crystallographic c-axis. The closely hatchedcircles represent Na atoms and the white circles represent K atoms. Thehatched regions represent LiO₄ tetrahedra, and the closely hatchedregions represent SiO₄ tetrahedra. The LiO₄ and SiO₄ tetrahedra arecorner- and edge-linked and form channels in which the Na and K atomsare arranged. The crystal structure is related to the crystal structureof AB3, AB7, AB8, AB9, AB13, AB14, AB15 and AB16.

In particular, two types of channels are contained in the crystalstructure. Exclusively K atoms are arranged in the first channels, whileNa and K atoms are arranged in the other channels. SiO₄ tetrahedra(closely hatched) are arranged in the form of a helix (FIG. 172) aroundthe channels in which exclusively K atoms are arranged. The Na atoms(closely hatched circles), within the channels in which Na and K atomsare arranged, are surrounded by SiO₄ tetrahedra in distorted tetrahedralfashion (black regions; FIG. 173). FIG. 172 shows the channel containingonly K atoms. FIG. 173 shows the channel containing K atoms and Naatoms. The sequence of the arrangement of the K atoms and Na atomswithin the channel is NaKKKNaKKK. The illustrations of the excerpts fromthe crystal structure in FIGS. 172 and 173 are perpendicular to thecrystallographic c-axis.

FIG. 174 shows crystallographic data of Na_(0.125)K_(0.875)Li₃SiO₄:Eu(AB17).

FIG. 175 shows atomic positions in the structure ofNa_(0.125)K_(0.75)Li₃SiO₄:Eu (AB17).

FIG. 176 shows anisotropic displacement parameters ofNa_(0.125)K_(0.875)Li₃SiO₄:Eu (AB17).

FIG. 177 shows a crystallographic evaluation of the X-ray powderdiffractogram of the seventeenth exemplary embodiment AB17. The diagramillustrates a comparison of the measured reflections with the calculatedreflections for Na_(0.125)K_(0.875)Li₃SiO₄:Eu. The upper part of thediagram shows the experimentally observed reflections (Mo K_(α1)radiation); the lower part of the diagram shows the calculatedreflection positions. The calculation was made on the basis of thestructure model for Na_(0.125)K_(0.875)Li₃SiO₄:Eu, as described in FIGS.171-176. Reflections of secondary phases are identified by *. Thecorrespondence of the reflections of the calculated powder diffractogramto the reflections of the measured powder diffractogram reveals acorrespondence of the crystal structure of single crystals and powdersof the phosphor.

The conversion LED in accordance with FIG. 178 has a layer sequence 2arranged on a substrate 10. The substrate 10 can be configured inreflective fashion, for example. A conversion element 3 in the form of alayer is arranged above the layer sequence 2. The layer sequence 2 hasan active layer (not shown), which emits a primary radiation having awavelength of 300 to 500 nm during operation of the conversion LED. Theconversion element is arranged in the beam path of the primary radiationS. The conversion element 3 comprises a matrix material such as, forexample, a silicone and particles of the phosphor (Rb_(0.5)Li_(0.5))Li₃SiO₄:Eu having an average grain size of 10 μm, which at least partlyconverts the primary radiation into a secondary radiation in the greenrange of the electromagnetic spectrum during operation of the conversionLED. The phosphor is distributed homogeneously in the matrix material inthe conversion element 3 within the scope of production tolerance. Theconversion element 3 is applied over the whole area above the radiationexit surface 2 a of the layer sequence 2 and above the side surfaces ofthe layer sequence 2 and is in direct mechanical contact with theradiation exit surface 2 a of the layer sequence 2 and the side surfacesof the layer sequence 2. The primary radiation can also emerge via theside surfaces of the layer sequence 2.

The conversion element 3 can be applied for example by injectionmolding, transfer molding or by spray coating methods. Moreover, theconversion LED has electrical contacts (not shown), the formation andarrangement of which are known to the person skilled in the art.

FIG. 179 shows a further exemplary embodiment of a conversion LED 1. Incomparison with FIG. 68, the conversion element 3 is shaped as a lamina.The lamina can consist of sintered-together particles of the phosphorand can thus be a ceramic lamina, or the lamina comprises, for example,glass, silicone, an epoxy resin, a polysilazane, a polymethacrylate or apolycarbonate as matrix material with particles of the phosphor embeddedtherein. The conversion element 3 is applied over the whole area abovethe radiation exit surface 2 a of the layer sequence 2. In particular,primary radiation does not emerge via the side surfaces of the layersequence 2, but rather predominantly via the radiation exit surface 2 a.The conversion element 3 can be applied on the layer sequence 2 by wayof an adhesion layer (not shown), for example composed of silicone.

The conversion LED 1 in accordance with FIG. 180 comprises a housing 11having a cutout. A layer sequence 2 is arranged in the cutout, saidlayer sequence having an active layer (not shown), which emits a primaryradiation having a wavelength of 300 to 460 nm during operation of theconversion LED. The conversion element 3 is shaped as potting of thelayer sequence 2 in the cutout and comprises a matrix material such as,for example, a silicone and a phosphor, for example KLi₃SiO₄:Eu, whichat least partly converts the primary radiation into a secondaryradiation that gives a white-colored luminous impression duringoperation of the conversion LED 1. It is also possible for the phosphorto be concentrated in the conversion element 3 spatially above theradiation exit surface 2 a. This can be achieved by sedimentation, forexample.

The present disclosure is not restricted to the exemplary embodiments bythe description on the basis of said exemplary embodiments. Rather, thepresent disclosure encompasses any novel feature and also anycombination of features, which in particular includes any combination offeatures in the patent claims, even if this feature or this combinationitself is not explicitly specified in the patent claims or exemplaryembodiments.

While the disclosed embodiments have been particularly shown anddescribed with reference to specific embodiments, it should beunderstood by those skilled in the art that various changes in form anddetail may be made therein without departing from the spirit and scopeof the disclosed embodiments as defined by the appended claims. Thescope of the disclosed embodiments is thus indicated by the appendedclaims and all changes which come within the meaning and range ofequivalency of the claims are therefore intended to be embraced.

The following exemplary embodiments pertain to further aspects of thisdisclosure:

Embodiment 1 is a lighting device comprising a phosphor having thegeneral molecular formula(MA)_(a)(MB)_(b)(MC)_(c)(MD)_(d)(TA)_(e)(TB)_(f)(TC)_(g)(TD)_(h)(TE)_(i)(TF)_(j)(XA)_(k)(XB)_(l)(XC)_(m)(XD)_(n):E,wherein

-   -   MA is selected from a group of monovalent metals which comprises        Li, Na, K, Rb, Cs, Cu, Ag and combinations thereof,    -   MB is selected from a group of divalent metals which comprises        Mg, Ca, Sr, Ba, Zn, Mn, Eu, Yb, Ni, Fe, Co and combinations        thereof,    -   MC is selected from a group of trivalent metals which comprises        Y, Fe, Cr, Sc, In, rare earth metals and combinations thereof,    -   MD is selected from a group of tetravalent metals which        comprises Zr, Hf, Mn, Ce and combinations thereof,    -   TA is selected from the group of monovalent metals which        comprises Li, Na, Cu, Ag and combinations thereof,    -   TB is selected from a group of divalent metals which comprises        Mg, Zn, Mn, Eu, Yb, Ni and combinations thereof,    -   TC is selected from a group of trivalent metals which comprises        B, Al, Ga, In, Y, Fe, Cr, Sc, rear earth metals and combinations        thereof,    -   TD is selected from a group of tetravalent metals which        comprises Si, Ge, Sn, Mn, Ti, Zr, Hf, Ce and combinations        thereof,    -   TE is selected from a group of pentavalent elements which        comprises P, Ta, Nb, V and combinations thereof,    -   TF is selected from a group of hexavalent elements which        comprises W, Mo and combinations thereof,    -   XA is selected from a group of elements which comprises F, Cl,        Br and combinations thereof,    -   XB is selected from a group of elements which comprises O, S and        combinations thereof,    -   XC=N,    -   XD=C,    -   E=Eu, Ce, Yb and/or Mn,    -   a+b+c+d=t    -   e+f+g+h+i+j=u    -   k+l+m+n=v    -   a+2b+3c+4d+e+2f+3g+4h+5i+6j−k−2l−3m−4n=w    -   0.8≤t≤1    -   3.5≤u≤4    -   3.5≤v≤4    -   (−0.2)≤w≤0.2 and    -   0≤m<0.875 v and/or v≥l>0.125 v.

Embodiment 2 is the lighting device according to embodiment 1, whereinthe phosphor has a crystal structure in which TA, TB, TC, TD, TE and/orTF are surrounded by XA, XB, XC and/or XD, and the resultant structuralunits are linked via common corners and edges to form athree-dimensional spatial network having cavities or channels and MA,MB, MC and/or MD are/is arranged in the cavities or channels.

Embodiment 3 is the lighting device according to embodiment 1 or 2,wherein the phosphor has the following general molecular formula:(MA)_(a)(MB)_(b)(TA)_(e)(TB)_(f)(TC)_(g)(TD)_(h)(XB)_(l)(XC)_(m),wherein

-   -   MA is selected from a group of monovalent metals which comprises        Li, Na, K, Rb, Cs, Cu, Ag and combinations thereof,    -   MB is selected from a group of divalent metals which comprises        Mg, Ca, Sr, Ba, Zn, Mn, Eu, Yb, Ni, Fe, Co and combinations        thereof,    -   TA is selected from a group of monovalent metals which comprises        Li, Na, Cu, Ag and combinations thereof,    -   TB is selected from a group of divalent metals which comprises        Mg, Zn, Mn, Eu, Yb, Ni and combinations thereof,    -   TC is selected from a group of trivalent metals which comprises        B, Al, Ga, In, Y, Fe, Cr, Sc, rare earths and combinations        thereof,    -   TD is selected from a group of tetravalent metals which        comprises Si, Ge, Sn, Mn, Ti, Zr, Hf, Ce and combinations        thereof,    -   XB is selected from a group of elements which comprises O, S and        combinations thereof,    -   XC=N    -   a+b=t    -   e+f+g+h=u    -   l+m=v    -   a+2b+e+2f+3g+4h−2l−3m=w    -   0.8≤t≤1    -   3.5≤u≤4    -   3.5≤v≤4    -   (−0.2)≤w≤0.2 and    -   0<m<0.875 v and/or v≥l>0.125 v.

Embodiment 4 is the lighting device according to embodiment 3, wherein

-   -   MA is selected from a group of monovalent metals which comprises        Li, Na, K, Rb, Cs and combinations thereof,    -   MB is selected from a group of divalent metals which comprises        Mg, Ca, Sr, Ba, Eu and combinations thereof,    -   TA is selected from a group of monovalent metals which comprises        Li, Na, Cu, Ag and combinations thereof,    -   TB is selected from a group of divalent metals which comprises        Eu,    -   TC is selected from a group of trivalent metals which comprises        B, Al, Ga, In and combinations thereof,    -   TD is selected from a group of tetravalent metals which        comprises Si, Ge, Sn, Mn, Ti and combinations thereof,    -   XB=O.

Embodiment 5 is the lighting device according to any of embodiments 1 to4, wherein the lighting device is a conversion light-emitting diode (1),comprising

-   -   a primary radiation source (2) configured to emit an        electromagnetic primary radiation during operation of the diode,    -   a conversion element (3) comprising the phosphor, said        conversion element being arranged in the beam path of the        electromagnetic primary radiation, wherein the phosphor is        configured at least partly to convert the electromagnetic        primary radiation into an electromagnetic secondary radiation        during operation of the lighting device.

Embodiment 6 is the lighting device according to any of embodiments 1 to5, wherein the following hold true for the phosphor:

-   -   a+b+c+d=1    -   e+f+g+h+i+j=4    -   k+l+m+n=4    -   a+2b+3c+4d+e+2f+3g+4h+5i+6j−k−2l−3m−4n=0 and    -   m<3.5.

Embodiment 7 is the lighting device according to any of embodiments 1 to6, wherein the phosphor has one of the following general molecularformulae:(MA)Li_(3−x)Si_(1−x)Zn_(x)Al_(x)O₄:E(MA)Li_(3−x)Si_(1-x)Mg_(x)Al_(x)O₄: E(MA)_(1−x′)Ca_(x′)Li₃Si_(1−x′)Al_(x′)O₄:E(MA)_(1−x″)Ca_(x″)Li_(3−x″),Si_(1−x″)Mg_(2x″)O₄:E(MA)Li_(3−2z)Mg_(3z)Si_(1−z)O₄:E or(MA)Li₃Si_(1−2z′)Al_(z′)P_(z′)O₄:E, wherein0≤x≤1,0≤x′≤1,0≤x″≤1,0≤z≤1,0≤z′≤0.5 and E is selected from a group which comprises Eu, Ce, Yb, Mnand combinations thereof.

Embodiment 8 is the lighting device according to any of embodiments 1 to6,

wherein the phosphor has one of the following general molecularformulae:(MA)_(1−y)Zn_(y)Li_(3−2y)Al_(3y)Si_(1−y)O_(4−4y)N_(4y):E,(MA)_(1−y*)Ca_(y*)Li_(3−2y*)Al_(3y*)Si_(1−y*)O_(4−4y*)N_(4y*):E,(MA)_(1−y***)Sr_(y***)Li_(3−2y**)Al_(3y**)Si_(1−y**)O_(4−4y**)N_(4y**):E(MA)_(1−y**)Eu_(y**)Li_(3−2y**)Al_(3y**)Si_(1−y**)O_(4−4y**)N_(4y**):E(MA)Li_(3−y′)Al_(y′)SiO_(4−2y′)N_(2y′):E,(MA)Li_(3−y″)Mg_(y″)SiO_(4−y″)N_(y″):E,(MA)_(1−w′″)Ca_(w′″)Li₃SiO_(4−w′″)N_(w′″):E,(MA)Li_(3−w′)Al_(2w′)Si_(1−w′)O_(4−w′)N_(w′):E,(MA)_(1−w″)Ca_(w″)Li_(3−w″)Si_(1−w″)Al_(2w″)O_(4−2w″)N_(2w″):E,wherein0<y*<0.875,0<y**<0.875,0<y***<0.875,0≤y<0.875,0≤y′≤1.75,0≤y′≤3,0≤w″′≤1,0≤w′≤1,0≤w″≤1 and E is selected from a group which comprises Eu, Ce, Yb, Mn andcombinations thereof.

Embodiment 9 is the lighting device according to any of embodiments 1 to6,

wherein the phosphor has the following general molecular formula: (MA)₁(TA)₃(TD)₁(XB)₄:E, wherein

MA is selected from a group of monovalent metals which comprises Li, Na,K, Rb, Cs and combinations thereof,

-   -   TA=Li    -   TD=Si and    -   XB=O and E is selected from a group which comprises Eu, Ce, Yb,        Mn and combinations thereof.

Embodiment 10 is the lighting device according to embodiment 9,

wherein the phosphor has the general formula(Na_(r)K_(1−r))₁(TA)₃(TD)₁(XB)₄:E,(Rb_(r′)Li_(1−r′))₁(TA)₃(TD)₁(XB)₄:E,(K_(1−r″−r′″)Na_(r″)Li_(r′″))₁(TA)₃(TD)₁(XB)₄:Eor (Rb_(r*)Na_(1−r*))₁(TA)₃(TD)₁(XB)₄:E,wherein0≤r≤1,0≤r′≤1,0<r″<0.5,0<r′″<0.5,0<r*<1and E is selected from a group which comprises Eu, Ce, Yb, Mn andcombinations thereof.

Embodiment 11 is the lighting device according to embodiment 9, whereinthe phosphor has the formula(Cs,Na,K,Li)₁(TA)₃(TD)₁(XB)₄:E.

Embodiment 12 is the lighting device according to embodiment 9, whereinthe phosphor has the formula (Na_(r)K_(1-r))₁(TA)₃(TD)₁(XB)₄:E or(Na_(r)K_(1−r))Li₃SiO₄:E, wherein 0.05<r≤0.2, preferably 0.1<r≤0.2 andE=Eu, Ce, Yb and/or Mn.

Embodiment 13 is the lighting device according to embodiment 8, whereinthe phosphor has the formulaNa_(1−y*)Ca_(y*)Li_(3−2y*)Al_(3y*)Si_(1−y*)O_(4−4y*)N_(4y*):E, wherein0<y*<0.875, preferably 0<y*≤0.5 and E is selected from a group whichcomprises Eu, Mn, Ce, Yb and combinations thereof.

Embodiment 14 is the lighting device according to embodiment 8, whereinthe phosphor has the formulaNa_(1−y*)Eu_(y**)Li_(3−2y**)Al_(3y**)Si_(1−y**)O_(4−4y**)N_(4y**):E,wherein 0<y**<0.875, preferably 0<y**<0.5 and E is selected from a groupwhich comprises Eu, Mn, Ce, Yb and combinations thereof.

Embodiment 15 is the lighting device according to any of embodiments 1to 6, wherein the phosphor has the formula(MB)Li_(3−2x**)Al_(1+2x**)O_(4−4x**)N_(4x**):E, wherein 0<x**<0.875, MBis selected from a group of divalent metals which comprises Mg, Ca, Sr,Ba, Zn and combinations thereof, and E is selected from a group whichcomprises Eu, Mn, Ce, Yb and combinations thereof.

Embodiment 16 is the lighting device according to embodiment 15, whereinthe phosphor has the formulaSrLi_(3−2x**)Al_(1+2x**)O_(4−4x**)N_(4x**):Eu, wherein 0<x**<0.875,preferably 0.125≤x**<0.875 or 0.125≤x**≤0.5, very particularlypreferably 0.125≤x**≤0.45.

Embodiment 17 is the lighting device according to any of embodiments 1to 6, wherein the phosphor has the formula(MB)(Si_(0.25)Al_(−1/8+r**/2)Li_(7/8−r**/2))₄ (O_(1−r**)N_(r**))₄:E,wherein 0.25≤r**≤1, MB is selected from a group of divalent metals whichcomprises Mg, Ca, Sr, Ba and combinations thereof, and E=Eu, Ce, Yband/or Mn.

Embodiment 18 is the lighting device according to embodiment 7,

which is configured to emit a blue radiation, wherein the phosphor hasthe formula(Na_(r)K_(1−r))₁(TA)₃(TD)₁(XB)₄:Ewhere 0.4<r≤1 (Rb_(r*)Na_(1-r*))₁(TA)₃(TD)₁(XB)₄:E where 0<r*<0.4 or(Cs,Na,Rb,Li)₁(TA)₃(TD)₁(XB)₄: E, (Cs,Na,K)₁(TA)₃(TD)₁(XB)₄:E and(Rb,Na,K)₁(TA)₃(TD)₁(XB)₄:E.

Embodiment 19 is the use of a lighting device according to any ofembodiments 1 to 18 for the backlighting of display devices, inparticular of displays.

Embodiment 20 is a display device comprising a lighting device accordingto any of embodiments 1 to 18.

LIST OF REFERENCE SIGNS

-   ppm Parts per million-   λpeak Peak wavelength-   λdom Dominant wavelength-   AB Exemplary embodiment-   g Gram-   E Emission-   mmol Millimol-   Mol % Mol percent-   R_(inf) Diffuse reflection-   lm Lumen-   W Watt-   LER Luminous efficiency-   LED Light-emitting diode-   CRI Color rendering index-   CCT Correlated color temperature-   R9 Color rendering index-   K/S Kubelka-Munk function-   K Kelvin-   cm Centimeter-   nm Nanometer-   ° 2θ Degree 2 Theta-   I, II, III, IV, V, VI X-ray powder diffractogram-   Ew White point-   KL Conversion line-   T Temperature-   ° C. Degree Celsius-   1 Conversion LED-   2 Layer sequence/semiconductor chip-   2 a Radiation exit surface-   3 Conversion element-   10 Substrate-   11 Housing-   S Beam path of the primary radiation

What is claimed is:
 1. A lighting device comprising a phosphor having the general molecular formula (MB)Li_(3−2x**)Al_(1+2x**)O_(4-4x**)N_(4x**):E, wherein 0<x**<0.875, MB is selected from a group of divalent metals which comprises Mg, Ca, Sr, Ba, Zn and combinations thereof, and E is selected from a group which comprises Eu, Ce, Yb and combinations thereof.
 2. The lighting device as claimed in claim 1, wherein 0.125≤x**<0.875.
 3. The lighting device as claimed in claim 1, wherein the phosphor has the formula SrLi_(3-2x**)Al_(1+2x**)O_(4−4x**)N_(4x**):Eu, wherein 0<x**<0.875.
 4. The lighting device as claimed in claim 3, wherein 0.125≤x**<0.875.
 5. The lighting device as claimed in claim 1, wherein the phosphor crystallizes in a tetragonal crystal system.
 6. The lighting device as claimed in claim 5, wherein the phosphor crystallizes in the space group I4/m.
 7. The lighting device as claimed in claim 1, wherein the lighting device is a conversion light-emitting diode comprising: a primary radiation source configured to emit an electromagnetic primary radiation during operation of the diode, a conversion element comprising the phosphor, said conversion element being arranged in the beam path of the electromagnetic primary radiation, wherein the phosphor is configured at least partly to convert the electromagnetic primary radiation into an electromagnetic secondary radiation during operation of the lighting device.
 8. The lighting device as claimed in claim 1, wherein MB is selected from a group consisting of Ca, Sr, Ba, Zn, and combinations thereof.
 9. The lighting device as claimed in claim 1, wherein E is Eu.
 10. A lighting device comprising a phosphor having the general molecular formula (MB)Li_(3−2x**)Al_(1+2x**)O_(4−4x**)N_(4x**):Eu, wherein 0<x**<0.875, MB is selected from a group of divalent metals which comprises Ca, Sr, Ba, Zn and combinations thereof.
 11. The lighting device as claimed in claim 1, wherein the phosphor emits a secondary radiation in the blue to blue-green spectral range of the electromagnetic spectrum.
 12. The lighting device as claimed in claim 1, wherein the phosphor emits a secondary radiation in the blue to green-yellow spectral range of the electromagnetic spectrum. 